TY - Generic T1 - Assimilating Subsampled Airborne Lidar: How Much Lidar is Enough? T2 - 87th Annual Western Snow Conference Y1 - 2019 A1 - Justin Pflug A1 - Jessica D. Lundquist KW - assimilation KW - distributed modeling KW - LiDAR KW - snow patterns KW - tradespace AB -

Airborne lidar snow depth retrievals are vital for water resource management in basins with limited snow observations. However, airborne lidar remains impractical to collect frequently over large domains due to the high economic cost. In this study, we investigated the extent to which lidar coverage improved modeled snow evolution using a distributed model and assimilation scheme. Full-coverage Airborne Snow Observatory snow depth data in Tuolumne, California and the Olympic Mountains of Northwest Washington State were used as a baseline in which to test the improvement in modeled snow water resources when optimizing flight frequency, timing, and spatial coverage. Collections over multiple seasons in Tuolumne were also used to investigate the impact when assimilating observed snow patterns. Our results indicate that errors in distributed models make snow depth difficult to determine at fine spatial resolutions. However, patterns from lidar in previous seasons are informative enough to train modeled accumulation in following years, therefore reducing the need for repeated, full lidar collections.

JF - 87th Annual Western Snow Conference CY - Reno, NV UR - /files/PDFs/2019Pflug.pdf ER - TY - Generic T1 - Avalanche in Western Canada - Who is in Charge? T2 - 86th Annual Western Snow Conference Y1 - 2018 A1 - Jerry Toupin AB -

Every year several centimeters (feet) of snow fall in Canada. In fact, this land remains one of the snowiest countries in the world as more than 1000 cm of snow may fall in Western Canada in certain parts of the Canadian Rockies (British Columbia, Alberta, Yukon and the Northwest Territories) from as early as September to late May or yearlong for some summits (peaks). Avalanche is a common phenomenon for this part of North America and with more and more human activities ranging from infrastructure to backcountry trips. Fatalities, road and rail closures and delays are on the rise and costing millions of dollars to the Canadian economy.

In the past few decades, Canada has developed a high level of expertise to better control avalanche and save lives. This article depicts how the Canadian army (National Defense and the Canadian Forces), Parks Canada, the Canadian Avalanche Association, Avalanche Canada (Center) and several other stakeholders have developed and implemented tools and methods to protect everybody. (KEYWORDS: avalanche, monitoring, awareness, protection, winter, snow, Western Canada)

JF - 86th Annual Western Snow Conference CY - Albuquerque, New Mexico UR - /files/PDFs/2018Toupin.pdf ER - TY - Generic T1 - Are Model Complexity and Transferability Antithetical? Insights from Validation of a Variable-Complexity Snow Model on New Conditions T2 - 85th Annual Western Snow Conference Y1 - 2017 A1 - A.C. Lute A1 - Charles Luce AB -

The related challenges of predictions in ungauged basins and predictions in ungauged climates point to the
need to develop environmental models that are transferable across both space and time. Hydrologic modeling has
historically focused on modelling one or only a few basins using highly parameterized conceptual or physically
based models. However, model parameters and structures have been shown to change significantly when calibrated
to new basins or time periods, suggesting that model complexity and model transferability may be antithetical.

JF - 85th Annual Western Snow Conference CY - Boise, Idaho UR - /files/PDFs/2017Lute.pdf ER - TY - Generic T1 - An Assessment of Differences in Gridded Precipitation Datasets in Complex Terrain T2 - 84th Annual Western Snow Conference Y1 - 2016 A1 - Brian Henn A1 - Andrew J. Newman A1 - Ben Livneh A1 - Christopher Daly A1 - Jessica D. Lundquist AB -

Hydrologic modeling and other geophysical applications are sensitive to precipitation forcing data quality, and there are known challenges in spatially distributing gauge-based precipitation over complex terrain. We conduct a comparison of six high-resolution, daily and monthly gridded precipitation datasets over the Western United States. We compare the long-term average spatial patterns, and interannual variability of water-year total precipitation, as well as multi-year trends in precipitation across the datasets. We find that the greatest absolute differences among datasets occur in high-elevation areas and in the maritime mountain ranges of the Western United States, while the greatest percent differences among datasets relative to annual total precipitation occur in arid and rain-shadowed areas. Differences between datasets in some high-elevation areas may exceed 200 mm yr-1 on average, and relative differences range from 5-60% across the Western United States. (KEYWORDS:  orographic precipitation, precipitation uncertainty, hydrologic modeling, distributed datasets)

JF - 84th Annual Western Snow Conference CY - Seattle, Washington UR - /files/PDFs/2016Henn.pdf ER - TY - Generic T1 - Above-Canopy Snow Transport Rate in the Central Colorado Subalpine Zone T2 - 82nd Annual Western Snow Conference Y1 - 2014 A1 - Charles F. Leaf KW - Colorado KW - forest canopy KW - snow transport KW - subalpine AB -

The principles of aerodynamics govern snow transport in open terrain and also the transport of snow within and just above the forest canopy. Only in the last forty years or so, have theories been developed and field tested for wind-driven snow transport above forest canopies. This report presents a seamless transition between the two phenomena.

JF - 82nd Annual Western Snow Conference T3 - Proceedings of the Western Snow Conference CY - Durango, Colorado UR - sites/westernsnowconference.org/PDFs/2014Leaf.pdf ER - TY - Generic T1 - Airborne Snow Observatory: Hetch Hetchy Basin Snow Water Equivalent Time Series, 2013 T2 - 82nd Annual Western Snow Conference Y1 - 2014 A1 - Bruce J. McGurk A1 - Thomas H. Painter KW - Hetch Hetchy KW - LiDAR KW - PRMS KW - runoff forecasting KW - Snow water equivalent KW - Tuolumne AB -

The Airborne Snow Observatory (ASO) 2013 demonstration mission collected detailed basin-wide snow information for portions of the Tuolumne Basin in California and the Uncompahgre Basin in Colorado. The ASO uses an imaging spectrometer and LiDAR systemmounted in an aircraft for collecting snow depth and snow albedo. Snow depth is combined with a calculated density field to produce distributed snow water equivalent. Weekly flights over the Tuolumne produced both basin-wide and sub-basin SWE estimates that were used in the USGS Precipitation Runoff Model to provide runoff forecasts for Hetch Hetchy Reservoir, the source of 85% of the water supply for 2.5 million people on the San Francisco Peninsula. Information produced by the ASO data collection and PRMS modeling is designed to improve the ability of reservoir operators to more efficiently allocate the last half of the recession limb of snowmelt inflow and be more assured of meeting operational mandates.

JF - 82nd Annual Western Snow Conference T3 - Proceedings of the Western Snow Conference CY - Durango, Colorado UR - sites/westernsnowconference.org/PDFs/2014McGurk.pdf ER - TY - Generic T1 - Are Temperature-Index Models Appropriate for Assessing Climate Change Impacts On Snowmelt T2 - 82nd Annual Western Snow Conference Y1 - 2014 A1 - Mark S. Raleigh A1 - Martyn P. Clark KW - climate change KW - Energy balance KW - physically-based model KW - temperature-index model AB -

Robust projections of climate change impacts are critical for natural resource planning in snow-dominated watersheds. Numerous studies have applied temperature-index (TI) snow models using calibrated parameter sets from the historic period, and estimate climate change impacts by forcing TI snow models with different climate scenarios. However, this methodology is questionable because (1) it assumes stationarity in model parameters, (2) it assumes the climate change signal is embedded in temperature alone, and (3) it does not account for changes in the snowmelt energy balance in a warmer climate. Here we explore the relationships between TI melt factors and changes in climate to understand the reliability of TI models for quantifying climate change impacts on snow hydrology. We examine historic relationships between temperature and melt factors (derived from observations) at 510 SNOTEL sites across diverse hydroclimates. Results show that melt factors decrease with increasing mean annual temperature at 98.6% of the sites (76% with statistical significance), and decrease with declining peak SWE and earlier peak SWE timing at over 90% of the sites. The results imply that historically calibrated TI models will overestimate snowmelt rates when applied in a warmer climate, and therefore their usage in climate change studies is problematic.

JF - 82nd Annual Western Snow Conference T3 - Proceedings of the Western Snow Conference CY - Durango, Colorado UR - sites/westernsnowconference.org/PDFs/2014Raleigh.pdf ER - TY - Generic T1 - Analysis of Future Snow Conditions for the National Climate Assessment T2 - 81st Annual Western Snow Conference Y1 - 2013 A1 - Kunkel, Kenneth E. KW - climate assessment KW - projections KW - snowfall AB -

The Third National Climate Assessment Report is under development. To support this effort, regional analyses of climate conditions were conducted, focusing on both historical trends deduced from observations and future projections derived from climate model simulations. A recent project on snowfall trends generally found declining total snowfall in the western U.S. at cooperative observer sites. Since the 1990s, the area with extreme high seasonal snowfall has been well below the long-term mean. Climate model simulations show substantial future warming throughout the west. Precipitation is simulated to decrease in the Southwest and increase in the Northwest and Alaska. These results suggest future declining snowpack in the southwest.

JF - 81st Annual Western Snow Conference T3 - Proceedings of the Western Snow Conference CY - Jackson Hole, Wyoming UR - sites/westernsnowconference.org/PDFs/2013Kunkel.pdf ER - TY - Generic T1 - Airborne Snow Observatory: Next Generation of Basin Snow Measurement, Modeling, and Forecasting T2 - 81st Annual Western Snow Conference Y1 - 2013 A1 - McGurk, Bruce J. A1 - Painter, Thomas H. KW - Hetch Hetchy KW - LiDAR KW - PRMS KW - runoff forecasting KW - Snow water equivalent KW - Tuolumne AB -

The Airborne Snow Observatory (ASO) demonstration mission will collect detailed basin-wide snow information for portions of the Tuolumne Basin in California and the Uncompahgre Basin in Colorado in spring of 2013. The ASO uses an imaging spectrometer and LiDAR system mounted in an aircraft for collecting data allowing determination of snow water equivalent, snow depth, and snow albedo. Weekly flights over the Tuolumne will produce both basin-wide and detailed sub-basin SWE estimates that will be used in a hydrologic simulation model to improve the accuracy and timing of runoff forecasting tools used to manage Hetch Hetchy Reservoir, the source of 85% of the water supply for 2.5 million people on the San Francisco Peninsula. The USGS PRMS simulation model will be calibrated to the 459 square mile basin and will be updated at weekly time steps with both weather forecast data and distributed snow information from ASO flights to inform the reservoir operators of predicted inflow volumes and timing. Information produced by the ASO data collection and PRMS modeling is expected to improve the ability of reservoir operators to more efficiently allocate the last half of the recession limb of snowmelt inflow and be more assured of meeting operational mandates. This presentation will provide preliminary results from the project as it begins its first year.

JF - 81st Annual Western Snow Conference T3 - Proceedings of the Western Snow Conference CY - Jackson Hole, Wyoming UR - sites/westernsnowconference.org/PDFs/2013McGurk.pdf ER - TY - Generic T1 - An Algorithm to Estimate Traditional Snowfall Measurements from Ultrasonic Snow Depth Sensors at U.S. Observing Sites T2 - 81st Annual Western Snow Conference Y1 - 2013 A1 - Ryan, Wendy A. A1 - Doesken, Nolan J. KW - precipitation gauge KW - snowboard KW - snowfall KW - ultrasonic snow depth sensor AB -

The measurement of snowfall is a climatologically important variable measured at U.S. observing sites dating back to the late 1800’s. Snowfall is inherently difficult to measure due to wind redistribution, compaction and melting that can occur prior to a snowfall measurement taking place. With automation of many U.S. observing sites in the 1990’s, snowfall measurements were abandoned due to lack of technology to continue the measurements at many locations. This study aims to test the feasibility of restoring traditional snowfall measurements at automated stations using changes in snow depth from ultrasonic sensors. The ultrasonic sensors were installed in a triplicate configuration along with a Geonor precipitation gage and a wetness sensor for verification. Results show fairly good agreement between manual measurements and automated snowfall estimates. Differences are mainly due to low density snow that is not measured by the ultrasonic sensors and also does not register measureable precipitation in the Geonor gage. Wind driven events also cause problems for the algorithm, but overall these events were mainly less than 2.5 cm (1 inch) as manually measured but not estimated by the algorithm at all.

JF - 81st Annual Western Snow Conference T3 - Proceedings of the Western Snow Conference CY - Jackson Hole, Wyoming UR - sites/westernsnowconference.org/PDFs/2013Ryan.pdf ER - TY - Generic T1 - Analyzing the Impact of Climate Change on Monthly River Flows in California's Sierra Nevada and Southern Cascade Mountain Ranges T2 - 80th Annual Western Snow Conference Y1 - 2012 A1 - Gary J Freeman KW - climate change KW - hydroelectric KW - orographic KW - subbasin KW - unimpaired flow AB -

The impact of climate change on monthly river flows in California's Sierra Nevada and southern Cascade Mountain Ranges and its potential to impact hydroelectric production was analyzed to determine changes that have taken place in two successive 35-year periods during the past 70 years. Unimpaired monthly flows from both California's Department of Water Resources' (CDWR) Data Exchange Center's (CDEC) files and from Pacific Gas and Electric Company's (PG&E) operational subbasin runoff forecasting files for the Feather River were analyzed for comparison of the two periods. A notable change was the shift of snowmelt runoff from the April through July period into the month of March. March flows were larger for the more recent 35-year period for all of the flow points analyzed in the Sierra and southern Cascades including two subbasins on the upper North Fork Feather River where rain shadowed climate change impact has significantly reduced both snowmelt and water year runoff in the more recent 35-year period. The increase in March runoff appears to be a combination of mostly earlier snowmelt due to warming temperatures and from an increase in proportion of March precipitation that now occurs as rainfall. In northern California both the shift of snowmelt into March and the reduction of snowpack overall has resulted in reduced late spring and summer flows during the months of April through June. Subbasins south of the Yuba River have for the most part increased overall snowmelt runoff for the March 1 through July 31 period, while subbasins from the Yuba River north have remained either equal or declined in snowmelt runoff in recent years. Both increased elevation and orographic cooling seem to be critical for delaying the impacts of climate change on affecting spring and early summer runoff. For a rain-shadowed subbasin such as Lake Almanor, the recent 35-year period shows a 22% decline in the April through July runoff caused primarily from a combination of: 1) earlier snowmelt, 2) increased proportion of precipitation occurring as rainfall in recent years with less snowfall overall, and 3) reduced aquifer outflow from springs. (KEYWORDS: climate change, subbasin, unimpaired flow, orographic, hydroelectric)

JF - 80th Annual Western Snow Conference T3 - Proceedings of the Western Snow Conference PB - Omnipress CY - Anchorage, Alaska UR - sites/westernsnowconference.org/PDFs/2012Freeman.pdf ER - TY - Generic T1 - Application of a Wireless Sensor Network for Distributed Snow Water Equivalence Estimation T2 - 79th Annual Western Snow Conference Y1 - 2011 A1 - Moeser, C.D. A1 - Walker, M.J. A1 - Skalka, C. A1 - Frolik, J. KW - Sagehen Creek, wireless network, snow water equivalent, snow sensor, snow, snow depth, areal estimation AB - Snow accumulated in mountainous areas is the source of water supply for much of the western United States. Estimates of the expected amounts of annual discharge in rivers are based on snow water equivalence (SWE) measurements and regression models that have climate stability as an underlying assumption. The current data collection network for SWE provides sparse areal coverage. Inexpensive wireless sensor networks and simple estimation techniques could be used to extend the areal coverage of snow data to improve spatial resolution. We report results of deployment of a prototype wireless sensor network, Snowcloud, at the Sagehen Creek, CA experimental field station. The network reported snow depth and temperature from January-May, 2010. A simple estimate of SWE at each node was based on the assumption of stability of the ratio SWE/SD and predicted SWE with reasonable accuracy (average difference of +1.0 cm (0.4 in), standard deviation = 3.0 cm (1.2 in)). Regression analysis indicated significant associations (P<.05) between SWE and % canopy closure to the north, weekly total incoming solar radiation and monthly average temperature. These results indicate that wireless sensor networks measuring SD can be used to extend information from snow measurement sites accurately to give estimates of water availability in snowpack. JF - 79th Annual Western Snow Conference T3 - Proceedings of the 79th Annual Western Snow Conference PB - Western Snow Conference CY - Stateline, NV UR - sites/westernsnowconference.org/PDFs/2011Moeser.pdf ER - TY - Generic T1 - An Analysis of Long-Term Precipitation and Snow Water Equivalent Records in the Lake Tahoe and Truckee River Watersheds T2 - 77th Annual Western Snow Conference Y1 - 2009 A1 - Boyle, D.P. A1 - Schumer, R. A1 - Ashby, J. A1 - Klieforth, H. A1 - Makowski, A. A1 - Barth, C. A1 - Garner, C. KW - Precipitation observations, cloud-seeding, SWE, long-term records, Lake Tahoe, Truckee River AB - As part of the long-term Nevada Cloud Seeding Project, continuous manual measurements of storm precipitation and snow water equivalent (SWE) were made from 1966 through approximately 2001 at 29 sites throughout the Lake Tahoe and Truckee River watersheds in Nevada and California. Monthly values of precipitation for each of the sites have been estimated from the storm-based precipitation records from approximately 1968 through 1992. The processing of the remaining years of precipitation data and the entire period of record for the SWE measurements is underway and the entire data set will be available on the Nevada Water Resources Research Institute web site when completed. In this poster, we present an overview of this unique data set and its utility for: (1) improving the calibration of precipitation-runoff models to support river and reservoir operations in these watersheds; (2) testing and evaluating independent models (e.g., SNODAS, PRISM) designed to estimate the distribution of precipitation and SWE; and (3) estimating temporal and spatial statistics of precipitation and SWE in the watersheds. (Abstract only) JF - 77th Annual Western Snow Conference T3 - Proceedings of the 77th Annual Western Snow Conference PB - Western Snow Conference CY - Canmore, AB UR - sites/westernsnowconference.org/PDFs/2009Boyle.pdf ER - TY - Generic T1 - Assessing the Sensitivity of Wasatch Mountain Snowfall to Temperature Variations T2 - 77th Annual Western Snow Conference Y1 - 2009 A1 - Jones, L.P. A1 - Horel, J.D. KW - Wasatch Mountains, climate change, snow sensitivity, SNOTEL AB - Three methods are employed in this study to estimate the sensitivity of snow falling in the Wasatch Mountains of northern Utah to observed and projected changes in atmospheric temperature. Daily precipitation data from 1 October to 30 April 1979-2008 are examined from selected snowpack telemetry (SNOTEL) sites in northern Utah. Profiles of wet bulb temperature from near crest level (700 mb) to elevations along the mountain slopes of selected watersheds are estimated on days with precipitation soundings launched from the nearby Salt Lake City airport. The rain-snow line is assumed to correspond uniformly to the elevation of the wet bulb temperature equal to 1oC. Probability distribution functions of the fraction of precipitation falling as snow as a function of daily wet-bulb temperature are computed. The percentage of precipitation estimated to fall at wet-bulb temperatures in the range 0-1oC is assumed to switch from snow to rain if temperatures increase by 1oC. While the sensitivity to temperature depends strongly on elevation within the watershed, an increase in tropospheric temperatures of 1oC is estimated to lead to an 8-10% decrease in snow when averaged over the selected watersheds. JF - 77th Annual Western Snow Conference T3 - Proceedings of the 77th Annual Western Snow Conference PB - Western Snow Conference CY - Canmore, AB UR - sites/westernsnowconference.org/PDFs/2009Jones.pdf ER - TY - Generic T1 - Advances in Spatial Snow Modeling in Mountain Terrain T2 - 77th Annual Western Snow Conference Y1 - 2009 A1 - Kienzle, S.W. KW - Snow modeling, Rocky Mountains, precipitation type, lapse rate, air temperature, ACRU AB - Snow modeling is a demanding task in itself, but is even more demanding in complex terrain such as the Rocky Mountains. Snow modeling is carried out here with the ACRU agro-hydrological modeling system. A critical advancement was the development of a new method to separate snow and rain (Kienzle, 2008). As a further improvement, a new GIS based method that determines two daily minimum and maximum temperatures, based on incoming radiation calculations and leaf area index adjustments, is presented. This results in a daily, lapse rate dependent, air temperature to determine the precipitation type (snow or rain), and a near-ground air temperature to determine snow melt and evapotranspiration rates. A drawback in most distributed hydrological models is that area calculations are based on the horizontal plane rather than the sloped area. A method is presented to use two area calculations for each hydrological response unit: a horizontal area, which is used for precipitation input calculations, and a larger sloped area, which is used for all other hydrological processes, including interception, sublimation, snow melt, soil moisture, or groundwater recharge. JF - 77th Annual Western Snow Conference T3 - Proceedings of the 77th Annual Western Snow Conference PB - Western Snow Conference CY - Canmore, AB UR - sites/westernsnowconference.org/PDFs/2009Kienzle.pdf ER - TY - Generic T1 - Assessing the Impacts of Global Warming on Snowpack in the Washington Cascades T2 - 76th Annual Western Snow Conference Y1 - 2008 A1 - Casola, J.H. A1 - Cuo, L. A1 - Livneh, B. A1 - Lettenmaier, B.P. A1 - Stoelinga, M. A1 - Mote, P.W. A1 - Wallace, J.M. KW - Snowpack decline, global warming, Washington Cascades, temperature AB - The decrease in mountain snowpack attributable to global warming is difficult to estimate in the presence of the large year-to-year natural variability in observations of snow water equivalent (SWE). A more robust approach for inferring the impacts of global warming is to estimate temperature sensitivity of spring snowpack and multiply it by putative past and future temperature rises attributable to global warming. Estimates of sensitivity can be obtained from (a) geometric considerations regarding the change in the climatological snow line resulting from warming, (b) regression of historical April 1 SWE measurements upon mean winter temperatures, (c) a hydrological model forced by daily temperature and precipitation observations, and (d) the distribution of precipitation versus temperature at SNOTEL stations. All four methods yield an estimated 20% loss of spring snowpack for 1deg C warming; considering warming-induced precipitation increases, the sensitivity would decrease to 16%. Using various rates of temperature rise over the Northern Hemisphere, it is estimated that spring snow water equivalent in the Cascades portion of the Puget Sound drainage basin should have declined by 8-16% over the past 30 years due to global warming and it can be expected to decline by another 11-21% by 2050. JF - 76th Annual Western Snow Conference T3 - Proceedings of the 76th Annual Western Snow Conference PB - Western Snow Conference CY - Hood River, OR UR - sites/westernsnowconference.org/PDFs/2008Casola.pdf ER - TY - Generic T1 - Assessing the Representativeness of the NRCS SNOTEL System at a Basin-Wide Scale T2 - 76th Annual Western Snow Conference Y1 - 2008 A1 - Nolin, A.W. A1 - Brown, A. KW - NRCS, SNOTEL, basin scale, Willamette Basin, climate change AB - Information from the NRCS SNOTEL system is used throughout the West for streamflow forecasting, disaster preparedness and scientific research. Measurements taken from the network are often fed into climate models where they can be used to analyze patterns and illustrate changes. Within the Willamette Basin the majority of the network falls within mid range elevations of 1000-1500 meters. While there are few sites located below 1000 meters, there is no instrumentation above 1500 meters. The upper elevations make up a relatively small proportion of the entire basin, however, they do account for about 50 percent of the total snow covered area. Projected climate warming in the Pacific Northwest places an increased importance on accurate instrumentation and forecasting of snow covered areas. An analysis of the relationship between at-risk snow zones and the location of SNOTEL sites illustrates the need for the development of a methodology to insure the representativeness of the system. JF - 76th Annual Western Snow Conference T3 - Proceedings of the 76th Annual Western Snow Conference PB - Western Snow Conference CY - Hood River, OR UR - sites/westernsnowconference.org/PDFs/2008Nolin1.pdf ER - TY - Generic T1 - AgriMet: Automated Weather Observations for Evapotranspiration Modeling T2 - 76th Annual Western Snow Conference Y1 - 2008 A1 - Palmer, P.L. KW - AgriMet, irrigation, evapotranspiration, water use efficiency, crop coefficients, Kimberly-Penman, NRCS AB - Competition for limited water resources in the western United States continues to increase. To this end, the Bureau of Reclamation and Bonneville Power Administration partnered to create a network of automated agricultural weather stations - called AgriMet - in the Pacific Northwest in the 1980's. These stations collect and telemeter the meteorological parameters required to model crop evapotranspiration (ET). The network started with three stations in 1983, but has since grown to over 60 stations in Reclamation's Pacific Northwest region, 22 stations in the Great Plains Region in western Montana, and seven stations in the Mid Pacific region. These automated weather stations transmit their data hourly by the GOES satellite, and the information is used in the Kimberly-Penman 1982 evapotranspiration model to compute reference ET at each station. Crop coefficients are then applied to estimate water use for specific crops grown at each station for every day of the growing season. Use of AgriMet information in irrigation scheduling results in water and energy savings, reduced soil erosion, and protection of surface and ground water supplies. Near real time hourly weather data from AgriMet is also used for a variety of applications, including peak power load forecasting, agricultural frost protection, and short term weather forecast verification. JF - 76th Annual Western Snow Conference T3 - Proceedings of the 76th Annual Western Snow Conference PB - Western Snow Conference CY - Hood River, OR UR - sites/westernsnowconference.org/PDFs/2008Palmer.pdf ER - TY - Generic T1 - Applying Hydro-Climatological Research to Improve the Scientific Basis Of Local Watershed Decision-Making T2 - 75th Annual Western Snow Conference Y1 - 2007 A1 - Pattee, S. A1 - Ingersoll, T. A1 - Ward, J. KW - Watershed management, NASA, Dungeness River, Elwha AB - The North Olympic Peninsula Resource Conservation & Development (NOP RC&D) Council proposes to evolve a Solutions Network of local, regional and national organizations to provide watershed management teams with decision support through NASA-funded earth-sun research results. The NOP RC&D Council built a team of eight other major partners for this Project, including the NASA-funded Pacific NorthWest Regional Collaboratory (PNWRC); USDA Natural Resources Conservation Service; Pacific Northwest National Laboratory (PNNL) Idaho National Laboratory (INL); Olympic National Park (ONP); Clallam County; the National Association of RC&D Councils (NARC&DC) in Washington, DC; and Peninsula College (PC). The science portion involves applying hydro-climatological research, through the Hybrid hydrology model, to improve the scientific basis of local watershed decision making. A Solutions Network of User Groups, Research Scientists, and an Operation Center will be developed in the Dungeness and Elwha River watersheds during the first two years of this project. The Elwha River watershed is also the site of the largest dam removal project ever undertaken in the Nation and therefore posed additional opportunities to collaborate with Peninsula College, Olympic National Park, and the Elwha Research Consortium. JF - 75th Annual Western Snow Conference T3 - Proceedings of the 75th Annual Western Snow Conference PB - Western Snow Conference CY - Kailua-Kona, HI UR - sites/westernsnowconference.org/PDFs/2007Pattee.pdf ER - TY - Generic T1 - Annual Hydrochemical Fluxes from Alpine Subalpine Catchments in the Snowy Range, Wyoming T2 - 74th Annual Western Snow Conference Y1 - 2006 A1 - Hicks, D.L. A1 - Stednick, J.D. A1 - Fassnacht, S.R. A1 - Musselman, R.C. KW - Chemical fluxes, alpine catchment, Snow Range, dry deposition, Glacier Lake, hydrochemical output AB - Annual hydrochemical fluxes were calculated from 1989 to 2004 for two alpine-subalpine catchments, West and East Glacier Lake Outlets in the Snowy Range, Wyoming. Mean annual atmospheric deposition inputs within Glacier Lake Ecosystem Experiments Sites (GLEES) were 3.50 kg ha-1 yr-1 and 2.27 kg ha-1 yr-1 for inorganic nitrogen (NO3-N, HNO3-N and NH4-N) and sulfur (S), respectively. Dry deposition, as measured by CASTNET, accounts for less than 20% of total deposition for inorganic N and S. Lakes at GLEES are oligotrophic with a water quality specific conductance range of 5-15uS cm-1. During the 1989 sampling period at West Glacier Lake, cations were in decreasing order of Ca2+, Mg2+, Na+, K+, NH4-N and anion were in decreasing order of Cl-, SO4-S, and NO3-N. Chloride inputs were approximately equal to outputs suggesting proper accounting of precipitation and streamflow volumes. Hydrochemical outputs for major cations were greater than inputs and differences attributed to parent material and soil weathering. Inorganic N inputs are greater than outputs for annual hydrochemical fluxes from 1989-2004 suggest that GLEES catchments are accumulating N. JF - 74th Annual Western Snow Conference T3 - Proceedings of the 74th Annual Western Snow Conference PB - Western Snow Conference CY - Las Cruces, NM UR - sites/westernsnowconference.org/PDFs/2006Hicks.pdf ER - TY - Generic T1 - An Analysis of the Timing of Snow Course Measurement and the Potential Error Compared to April 1 Measurement in Utah T2 - 73rd Annual Western Snow Conference Y1 - 2005 A1 - Julaner, R.P. KW - Utah, snowpack, snow survey, runoff forecasting, SNOTEL, climate change, SWE prediction, April 1 AB -

Snowpack data collection began in an organized fashion in Utah during the late 1920's. The April 1 measurement soon proved to be one of the most important surveys with regard to water supply forecasting. These snow survey data, used historically as April 1 data were seldom actual April 1 measurements rather they were normally sampled at some time prior to April 1, in the latter part of March. In the way that Snow Survey Data were being used, principally in linear regression applications versus accumulated streamflow, this presented little error in the forecasting scheme. However, with the advent of telemetered snowpack information, there exist now two sets of data - those manual sites still measured during the end of March and the SNOTEL or electronic data which are actual April 1 values. The snow course data would underestimate the actual April 1 snowpack compared to the SNOTEL data set, however the magnitude of the error has not been determined. Climate change is being characterized by impacts seen in snowpack. For this type of analysis, the longer the data set, typically the better and more substantial and conclusive the findings. SNOTEL has a relatively short record being installed in the late 70's and early 80's but the snow course data reach back into the 20's, making the analysis far more long term. SNOTEL replaced many of the long term snow courses, thus reducing the pool of available long term data for analysis. This analysis compares the potential error associated with actual measurement timing to April 1 and provides an average correction factor for adjusting long term snow course data to observed SNOTEL data in Utah.

JF - 73rd Annual Western Snow Conference T3 - Proceedings of the 73rd Annual Western Snow Conference PB - Western Snow Conference CY - Great Falls, MT UR - sites/westernsnowconference.org/PDFs/2005JulanderB.pdf ER - TY - Generic T1 - AgriMet: Modeling Evapotranspiration for Irrigation Water Management T2 - 73rd Annual Western Snow Conference Y1 - 2005 A1 - Palmer, P.L. KW - AgriMet, irrigation, evapotranspiration, water use efficiency, crop coefficients, Kimberly-Penman, NRCS AB - In 1983, the U.S. Bureau of Reclamation and Bonneville Power Administration entered into a formal agreement to promote irrigation water use efficiency. This agreement resulted in the installation of a network of automated agricultural weather stations called AgriMet (for Agricultural Meteorology) in the Pacific Northwest. These stations collect and telemeter the meteorological parameters required to model crop evapotranspiration (ET). The information is used by irrigation districts, farmers, resource conservation agencies, and agricultural consultants for irrigation scheduling and related purposes. Since the initial installation of 3 stations in 1983, the network has grown to over 60 stations in Reclamation's Pacific Northwest region, 21 stations in the Great Plains Region in Montana, and seven stations in the Mid Pacific region. These automated weather stations transmit their data by the GOES satellite, and the information is used in the Kimberly-Penman 1982 evapotranspiration model to compute reference ET at each station. Crop coefficients are then applied to estimate water use for specific crops grown at each station for every day of the growing season. This information is available on the Internet, and is integrated into various on farm technical assistance programs by local agricultural consultants, the Cooperative Extension Service, and the USDA Natural Resources Conservation Service. Use of AgriMet information in irrigation scheduling results in water and energy savings, reduced soil erosion, and protection of surface and ground water supplies. Various agricultural consultants have reported water and power savings ranging from 15 to 50 percent (Dockter, 1996). Some irrigators have reported real savings of as much as $25 per acre in pumping costs when using AgriMet ET data to schedule their irrigations (Palmer, 2004). JF - 73rd Annual Western Snow Conference T3 - Proceedings of the 73rd Annual Western Snow Conference PB - Western Snow Conference CY - Great Falls, MT UR - sites/westernsnowconference.org/PDFs/2005Palmer.pdf ER - TY - Generic T1 - Arizona Chapter of Soil and Water Conservation Society Responds to Recovery Efforts of Arizona's Largest Wildfire T2 - 71st Annual Western Snow Conference Y1 - 2003 A1 - Dye, H. KW - Rodeo-Chediski wildfire, emergency watershed protection, check dams, erosion, Arizona AB - The Arizona Chapter of the Soil and Water Conservation Society (SWCS) coordinated a special field demonstration of practices used to prevent soil erosion following the 2002 Rodeo-Chediski wildfire. The Rodeo-Chediski wildfire in east central Arizona, fueled by severe drought conditions, consumed approximately 1,890 square kilometers (467,000 acres) of timber on National Forest, White Mountain Apache Nation, and private lands becoming the largest wildfire in Arizona's history. About 33 square kilometers (8,192 acres) of private land, including 491 homes and businesses were burned. The U.S. Department of Agriculture's Natural Resources Conservation Service (NRCS) approved a $2.9 million Emergency Watershed Protection (EWP) project initiating a large-scale fire recovery assistance program for private landowners affected by the wildfire. Arizona SWCS Chapter members, NRCS EWP detailees, and NRCS Earth Team volunteers joined forces to provide technical assistance and to demonstrate conservation practices, designed to protect lives and property from the effects of flooding and erosion resulting from the wildfire. Practices constructed during the demonstration included seeding, straw mulching, straw bale diversions and check dams, and contour wattles. As a result of the demonstration, a severely burned sub-watershed was completely treated and residents were provided with technical information to assist them with the recovery of their fire-damage property. JF - 71st Annual Western Snow Conference T3 - Proceedings of the 71st Annual Western Snow Conference PB - Western Snow Conference CY - Scottsdale, Arizona UR - sites/westernsnowconference.org/PDFs/2003Dye.pdf ER - TY - Generic T1 - Are Snow Resources on the Northern Plains and Prairies Dwindling? T2 - 71st Annual Western Snow Conference Y1 - 2003 A1 - Steppuhn, H. A1 - Cutforth, H.W. A1 - Judiesch, D. A1 - Wall, K.G KW - Swift Current, Saskatchewan, snowfall, temperature, prairie, declining water supply AB - Snow across the Northern Great Plains and Canadian Prairies constitutes a very essential natural resource. A study to determine if northern snow resources have changed in magnitude over the last forty years was initiated. Snow-course data measured in non-irrigated agricultural fields, near Swift Current, Saskatchewan, reflect the large year-to-year and within-year variability typical of wind-swept plains. This variability rendered direct measurement and detection of snow-resource change difficult. However, analyses of a combined set of daily climatological data (Nipher-shielded snowfall water-equivalent and depth of snow-on-the-ground) at Swift Current show a significant reduction within the last twenty years in the frequency of the number of days with snowcover depths exceeding 10 cm. This reduction was accompanied by a 3.6% increase in winter rainfall, a 17.2% decrease in snowfall, and a 48% decrease in the theoretical snowpack water equivalent. Average daily maximum temperature increased by almost 2 oC between the same early and recent decades. If the change in temperature increased snowpack losses by -34.4% and the conversion of snowfall to rainfall by 13.6%, then snow resources on the northern plains and prairies have diminished by 48%. Extrapolating these data throughout the region, one may conclude that snowcovers on the northern plains and prairies are indeed dwindling. JF - 71st Annual Western Snow Conference T3 - Proceedings of the 71st Annual Western Snow Conference PB - Western Snow Conference CY - Scottsdale, Arizona UR - sites/westernsnowconference.org/PDFs/2003Steppuhn.pdf ER - TY - Generic T1 - An assessment of the differences between three satellite snow cover mapping techniques T2 - 70th Annual Western Snow Conference Y1 - 2002 A1 - Bitner, D. A1 - Carroll, T. A1 - Cline, D. A1 - Romanov, P. KW - NOHRSC, Satellite snow cover, MODIS, NESDIS, Mapping comparison AB - The National Operational Hydrologic Remote Sensing Center (NOHRSC), National Weather Service(NWS), National Oceanic and Atmospheric Administration (NOAA) provides daily satellite-derived snow cover maps to support the NWS Hydrologic Services Program covering the coterminous U.S. and Alaska. This study compared the NOHRSC snow cover maps with new automated snow cover maps produced by the National Environmental Satellite, Data, and Information Service (NESDIS) and the snow cover maps created from the Moderate Resolution Imaging Spectroradiometer (MODIS) imagery. The purpose of this paper is to demonstrate and account for the differences that occur between the three different snow cover mapping techniques. Because each of these snow cover products uses data from different sensors at different resolutions, the data were degradd to the coarsest relevant resolution. In both comparisons, forest canopy density was examined as a possible explanatory factor to account for those differences. NOHRSC snow cover maps were compared to NESDIS snow cover maps for 32 different dates from November 2000 to February 2001. NOHRSC snow cover maps were also compared to MODIS snow cover maps in the Pacific Northwest and the Great Plains for 18 and 21 days, respectively, between March 2001 and June 2001. In the first comparison, where the NOHRSC product (approx. 1 km) was degraded to match the resolution of the NESDIS data (aprox. 5 km), the two products showed an average agreement of 96%. Forest canopy density data provided only weak explanation for the differences between the NOHRSC andthe NESDIS snow cover maps. In the second comparison, where the MODIS product (500 m) was degraded to match the resolution of the NOHRSC product for two sample areas, the agreement was 94% in the sample area in the Pacific Northwest, and 95% in the sample area in the Great Plains. JF - 70th Annual Western Snow Conference T3 - Proceedings of the 70th Annual Western Snow Conference PB - Western Snow Conference CY - Granby, Colorado UR - sites/westernsnowconference.org/PDFs/2002Bitner.pdf ER - TY - Generic T1 - Application of XTOP_PRMS model in Green Lakes Valley, Colorado front rabge: Runoff simulation and flowpath identification T2 - 70th Annual Western Snow Conference Y1 - 2002 A1 - Liu, F. A1 - Williams, M.W. A1 - Webb, R. A1 - Ackerman, T. KW - Stream runoff, Simulation modeling, PRMS, Flowpaths, Tracers AB - Stream runoff was simulated from 1996 to 2000 using XTOP_PRMS (coupling of TOPMODEL andPrecipitation Runoff Modeling System) model under Modular Modeling System at Martinelli and Green Lake 4catchments in Green Lakes Valley, Colorado Front Range. Two flowpaths determined by XTOP_PRMS model, surface flow (infiltration-excess overland flow) and subsurface flow, were compared against the flowpaths determined by mixing model using isotopic and chemical tracers. Three tracers (DOC, K/Si, and o^O) were used in mixing model to identify four flowpaths, i.e., overland, upper soil horizon, lower soil horizon, and base flow. Theresults showed that the runoff simulation using XTOP_PRMS model is reasonably successful for Martinellicatchment (8 ha in drainage area). The Nash-Sutcliffe efficiency is 0.76. The t-test of two means for paired sample showed that the difference between the observed and modeled runoff was not significantly different at a=0.05 at Martinelli catchment (n = 1611, p = 0.6). The flowpaths identified by XTOP_PRMS model matched the flowpaths determined by the tracer-mixing model reasonably well in magnitude, but poorly in pattern. The surface flow primarily occurred in the beginning of snowmelt at Martinelli as illustrated by the tracer-mixing model. Both runoff simulation and flowpath identification using XTOP_PRMS model were relatively poor at Green Lake 4 catchment, which has a drainage area of 220 ha. The runoff peaks observed in May and June were not captured in runoff simulation. The problem may be caused by poor understanding of behaviors of flowpath parameters and insensitivity of snowmelt to daily mean air temperature. JF - 70th Annual Western Snow Conference T3 - Proceedings of the 70th Annual Western Snow Conference PB - Western Snow Conference CY - Granby, Colorado UR - sites/westernsnowconference.org/PDFs/2002Liu.pdf ER - TY - Generic T1 - ANALYSIS OF THE SPATIAL VARIABILITY OF SNOW COVER DEPLETION IN AN ALPINE WATERSHED, TOKOPAH BASIN, SIERRA NEVADA, CALIFORNIA, U.S.A. T2 - 69th Annual Western Snow Conference Y1 - 2001 A1 - Molotch, N.P. A1 - T H Painter A1 - Colee, M.T. A1 - Rosenthal, W. A1 - Dozier, J. A1 - Bales, R.C. KW - Snow covered area, Spatial variability, Tokopah Basin AB -

In this study we quantified the spatial and temporal depletion of snow covered area (SCA) in order to obtain estimates of peak snow water equivalence (SWE) in the 19.1 km2 Tokopah Basin. We sought to answer the following questions: How do we improve the use of snow cover depletion curves by incorporating additional data and spatial analysis? How can we use snow cover depletion curves to estimate peak SWE earlier in the snowmelt season and continue to have leverage to update our estimates throughout the ablation season? What meteorological fields or combination of meteorological fields yield the most leverage in updating SWE estimates? In order to quantify snow cover depletion at different elevations and under different topographic environments, we analyzed snow cover depletion patterns in different elevation zones and in sub-basins of varying topographic heterogeneighty. We used 30m remotely sensed SCA data, hourly meteorological data, ground-based surveys of SWE and a 30m digital elevation model (DEM). We generated depletion curves of SCA using two methods of varying complexity: SCA versus modeled accumulated degree-days and SCA versus modeled net radiation. We found that SWE over the basin during the April, May and June snow surveys was 995mm, 701mm and 283mm respectively. Degree-day accumulation produced decreases in SCA at lower elevations (<2823m) before SCA decreased at higher elevations (>3222m). Degree-day depletion curves did not represent observed temporal variability in SWE during the ablation season. Depletion curves using net radiation as the response variable proved to better represent temporal SWE variability. We found that incremental decreases in SCA at higher elevations (>3222m) resulted in a greater decrease of SWE than the corresponding SWE decrease at lower elevations (<2 82 3m)

JF - 69th Annual Western Snow Conference T3 - Proceedings of the 69th Annual Western Snow Conference PB - Western Snow Conference CY - Sun Valley, Idaho UR - sites/westernsnowconference.org/PDFs/2001Molotch.pdf ER - TY - Generic T1 - ANTHROPOGENIC CLIMATE CHANGE AND SNOW IN THE PACIFIC NORTHWEST T2 - 69th Annual Western Snow Conference Y1 - 2001 A1 - Mote, P.W. A1 - Hamlet, A.F. KW - climate change AB -

The Pacific Northwest is unusually vulnerable to a warning climate owing to its heavy reliance on snowpack to store water for summer use. This paper outlines the state of global climate science and describes efforts by the Climate Impacts Group at the University of Washington to understand how a warming, of plausible magnitude could affect the Pacific Northwest, specifically with regard to streamflow and snowpack.

JF - 69th Annual Western Snow Conference T3 - Proceedings of the 69th Annual Western Snow Conference PB - Western Snow Conference CY - Sun Valley, Idaho UR - sites/westernsnowconference.org/PDFs/2001Mote.pdf ER - TY - Generic T1 - Automated spectro-goniometer: A robitic arm for the measurement of snow bi-directional reflectance distribution function T2 - 68th Annual Western Snow Conference Y1 - 2000 A1 - T H Painter A1 - Paden, B.E. A1 - Dozier, J. KW - Instrumentation, Snow measurements, Snow properties AB - We describe the UCSB Automated Spectro-Goniometer (ASG), a two-axis robotic arm paired with a field spectroradiometer for the rapid and accurate measurement of the optical bi-directional reflectance distribution function (BRDF) of snow. Improvements in radiative transfer models and remote sensing algorithms for snow properties require a more accurate characterization of the angular distribution of reflectance of snow. Previous measurements of snow BRDF have been incomplete with respect to one or more of spectral range, spectral resolution, angular resolution and sampling, solar zenith sampling, and snow characterization. The kinematics of the ASG may be described by Rodrigues ' fonnula for a 2 degree of freedom arm. We describe the forward kinematics for the ASG and then solve the inverse problem from given view angle to necessary rotation about each axis. Its two-dimensional hemispheric sampling space facilitates the measurement of spectral reflectance from snow into any direction. The ASG will usually sample a 10deg hemispheric grid at a 0.5 Hz sampling rate. We will also sample the solar principal plane at 1deg angular resolution at 0.5 Hz sampling rate. With a total weight of 41 kg, the ASG is easily portable by an individual via sled. JF - 68th Annual Western Snow Conference T3 - Proceedings of the 68th Annual Western Snow Conference PB - Western Snow Conference CY - Port Angeles, Washington UR - sites/westernsnowconference.org/PDFs/2000Painter.pdf ER - TY - Generic T1 - Atlantic ocean atmosphere interactions and snowfall in southern New England T2 - 65th Annual Western Snow Conference Y1 - 1997 A1 - Hartley, S. KW - Atlantic Ocean, Ocean circulation, Ocean temperature, Seasonal snowfall AB - This paper examines in further detail a previously identified inverse association between seasonal snowfall totals in southern New England and sea surface temperature anomalies (SSTAs) in the adjacent Atlantic Ocean. Variations of western Atlantic SSTAs and of the rnid-tropospheric circulation over North America and the adjacentAtlantic Ocean during the cold-season months ofOctober-March are each examined by principal component analysis.Canonical correlation analysis identifies the dominant modes ofjoint variability (contemporaneous and lagged) between Atlantic SST As and the atmospheric circulation. Comparisons are made between HIGH-SNOW and LOW-SNOW winters. Results suggest that the rnid-tropospheric circulation of December has a disproportionate influence on seasonal snowfall. Persistence of Atlantic SST As established partly through atmosphere-ocean coupling in the late fall/early winter is proposed as a possible linkage. The extent to which the SST As then influence precipitation form is still currently under investigation, but there are indications that SST As might influence the Atlantic Coast storm track, as well as air temperatures in southern and coastal New England. JF - 65th Annual Western Snow Conference T3 - Proceedings of the 65th Annual Western Snow Conference PB - Western Snow Conference CY - Banff, Alberta UR - sites/westernsnowconference.org/PDFs/1997Hartley.pdf ER - TY - Generic T1 - Acumulation of intercepted snow in the boreal forest: Measurements and modelling T2 - 65th Annual Western Snow Conference Y1 - 1997 A1 - Hedstrom, N.R. A1 - Pomeroy, J.W. KW - Interception, Modeling AB - A new snowfall interception model is introduced. The model incorporates physically-based processes to scale from the branch to canopy. Previous models of snow interception have neglected the persistence of intercepted snow load and the effects of temperature on maximum intercepted load and hence have only been applicable to climates where snow is regularly and quickly lost from the canopy. To investigate snow interception at the forest stand scale, measurements of above and subcanopy snowfall, accumulation of snow on the ground and the load of snow intercepted by a suspended, full-size conifer were collected from boreal forest spruce and pine stands. These data show that interception increases with increasing snowfall, to a point when the intercepted load overcomes the strength of branches to support it. Hence, the interception efficiency decreases with snow load and amount of fresh snowfall. Leaf area index, tree species and initial snow load determine the maximum canopy snow storage. The maximum storage, canopy coverage and snowfall are used to calculate snow interception for a canopy, presuming exponential decay in incremental interception as the amount of snowfall increases. The sensitivity of the model to temperature, wind speed and other factors is examined. This method can be used to calculate snow interception over an entire winter period using relatively standard meteorological and forest inventory variables. JF - 65th Annual Western Snow Conference T3 - Proceedings of the 65th Annual Western Snow Conference PB - Western Snow Conference CY - Banff, Alberta UR - sites/westernsnowconference.org/PDFs/1997Hedstrom.pdf ER - TY - Generic T1 - Application of SLURP hydrological model to a sub-arctic basin T2 - 65th Annual Western Snow Conference Y1 - 1997 A1 - Li, B. A1 - Kite, G. A1 - Haberlandt, U. KW - Grid model, Model application, Snow accummulation, Snow depletion AB - The SLURP model developed at NHRI, is a distributed conceptual model which simulates the behaviour of a watershed by carrying out vertical water balances for each element of a matrix of land covers and subareas of a watershed and then routing the resulting runoff between subareas. The model is able to simulate snowpack accumulation and depletion, groundwater response of watersheds, and rainfall and snowmelt generated streamflow. This study describes an approach of applying the SLURP hydrological model to a mountainous sub-arctic streamflow of Wolf Creek Basin. In this sub-arctic region, annual peak flow is generally dominated by snowmelt. As a research basin, the Wolf Creek basin has been equipped with instruments to measure the snow depth and density. A procedure to convert snow data time series into winter precipitation required by SLURP is developed. The generated winter precipitation data, together with other related climate data from three meteorological stations within the basin were used for both model calibration and model verification. Two years of streamflow data were tested with good results obtained for the calibration period 1994-1995 and somewhat lesser for the verification period 1995-1996. JF - 65th Annual Western Snow Conference T3 - Proceedings of the 65th Annual Western Snow Conference PB - Western Snow Conference CY - Banff, Alberta UR - sites/westernsnowconference.org/PDFs/1997Li.pdf ER - TY - Generic T1 - Applying the National Weather Service River Forecast System (NWSRFS) interactive forecast program to basins in Northwest Washington T2 - 64th Annual Western Snow Conference Y1 - 1996 A1 - Laurine, D. A1 - Hughes, S. A1 - Younger, M. A1 - Orwig, C. KW - Forecasting, Models, NWSRFS AB - The Northwest River Forecast Center has, during the past year, completed calibrating the National Weather Service River Forecast (NWSRFS) model in Northwest Washington. The next step in the process was to set the calibrated river basins up for the Interactive Forecast Program (IFP). This task requires defining headwater basins, routing reaches, reservoirs and downstream forecast points in the manner IFP demands. The IFP was run real-time during the 1995-96 winter forecast season. This paper will summarize the results of the model application in a complicated rain on snow environment. We will also present model enhancements resultant from this real-time test of the IFP . JF - 64th Annual Western Snow Conference T3 - Proceedings of the 64th Annual Western Snow Conference PB - Western Snow Conference CY - Bend, Oregon UR - sites/westernsnowconference.org/PDFs/1996Laurine.pdf ER - TY - Generic T1 - Application of principal components regression to streamflow forecasting T2 - 64th Annual Western Snow Conference Y1 - 1996 A1 - Smith, S. A1 - Weiss, E. KW - Forecasting, Regression, Statistical analysis AB -

B.C. Hydro adapted the techniques of principal component regression, cross-validation and a systematic search for optimal combinations of variables (Garen, 1993), to try to improve to the statistical accuracy of stream- flow volume forecast equations for the glaciated Bridge River basin in British Columbia. The paper will discuss the trade-offs that B.C. Hydro made in balancing the improvements in forecast accuracy using these techniques against other factors, such as preserving continuity in forecast equation structure from month to month, preferring short-term stations located within the basin to longer term stations outside the basin, and using the thirty-year normals period ( 1961-90) versus the historical period of record. Results for the Bridge River system demonstrate the balance that can be achieved between optimizing forecast accuracy and selecting variables and stations which make the forecast equations more physically rational.

JF - 64th Annual Western Snow Conference T3 - Proceedings of the 64th Annual Western Snow Conference PB - Western Snow Conference CY - Bend, Oregon UR - sites/westernsnowconference.org/PDFs/1996SmithB.pdf ER - TY - Generic T1 - An automated meteorological data validation system for the Soil Conservation Service SNOTEL network T2 - 62nd Annual Western Snow Conference Y1 - 1994 A1 - Cooley, K.R. A1 - Palmer, P.L. A1 - Searcy, M.L. KW - Data validation, Quality control, SNOTEL, Snow pillows AB - The SCS and ARS have collaborated on a project to develop an automated validation system for hydrometeorological data collected by the SCS SNOTEL system. The analysis portion of the software analyzes historical cata collected at individual SNOTEL sites, defining the expected ranges and daily changes of snowpack, precipitation, and air temperature data. The validation portion of the software screens real time data against these limits as well as performing other quality control tests. The implementation of this software into the SCS SNOTEL system will yield improved data quality for water supply forecasting and other resource management activities. Future planned developments include the incorporation of tests comparing data from nearby sites, and development of an algorithm for estimating missing or erroneous data. JF - 62nd Annual Western Snow Conference T3 - Proceedings of the 62nd Annual Western Snow Conference PB - Western Snow Conference CY - Sante Fe, New Mexico UR - sites/westernsnowconference.org/PDFs/1994Cooley.pdf ER - TY - Generic T1 - Assessment of temperature, precipitation and snow depth variations durnig the last 100 years in the former Soviet Union (FSU) T2 - 62nd Annual Western Snow Conference Y1 - 1994 A1 - Fallot, J-M. A1 - Barry, R.G. KW - Climate, Soviet Union AB - A climatological study is made of regional variations in temperature, precipitation ansd snow depth observed in the FSU during the last 50 - 100 years. Analysis, methods and some results of the January trends for these 3 parameters are presented. JF - 62nd Annual Western Snow Conference T3 - Proceedings of the 62nd Annual Western Snow Conference PB - Western Snow Conference CY - Sante Fe, New Mexico UR - sites/westernsnowconference.org/PDFs/1994Fallot.pdf ER - TY - Generic T1 - Assessing the importance of snowmelt water supply from 'historical' records of snow accumulation and runoff, Jhelum catchment, Pakistan Himalaya T2 - 62nd Annual Western Snow Conference Y1 - 1994 A1 - de Scally, F.A. KW - Jhelum River, Pakistan, Snow courses AB -

The importance of snowmelt water supply in the Jhelum River catchment is assessed by comparing the ‘historical’ records of winter snow accumulation and runoff in Pakistani sub-basins. The snow accumulation records, although only five to eight years long, represent the only such data available for this region of the western Himalaya. Strong statistical correlations are found to exist between point measurements of the annual maximum of snowpack water equivalent or total winter precipitation, and total annual runoff. Point measurements of total winter snowfall also show a generally significant correlation with annual runoff. Other evidence reinforces the conclusion that snowmelt is the dominant source of annual runoff, and indicates the potential value of such snow accumulation measurements for predicting seasonal and annual runoff, particularly since remotely sensed data have so far been difficult to obtain. However, such predictions may be complicated in this region by the effects of a continental-scale feedback mechanism between snow cover and the summer monsoon.

JF - 62nd Annual Western Snow Conference T3 - Proceedings of the 62nd Annual Western Snow Conference PB - Western Snow Conference CY - Sante Fe, New Mexico UR - sites/westernsnowconference.org/PDFs/1994deScally.pdf ER - TY - Generic T1 - An approach to assessing changes in snow cover: an example from the former Soviet Union T2 - 61st Annual Western Snow Conference Y1 - 1993 A1 - Barry, R.G. A1 - Armstrong, R.L. A1 - Krenke, A.N. KW - Climate change, Microwaves, Satellite photographs, Snowcover AB - The question of what are the most suitable indices of temporal change in snow cover conditions, and the most appropriate means for their detection is important in monitoring climate system changes. The extent and variability of seasonal snow cover is recognized to be an important climatic and hydrologic parameter. Trends in snow cover are also expected to serve as an indicator of any global climatic changes.Passive microwave data afford the possibility of all-weather mapping of daily snow extent, and potentially water equivalent, with a spatial resolution of 25-50 km is well suited for regional and global climate modeling. Newly-released snow depth data for stations in the former Soviet Union are described and for a ten-day average are compared with passive microwave-derived estimates. Possible sources of differences are discussed including problems related to wet snow, mountainous terrain and vegetation, as well as errors caused by the interpolation of station data used for validation. JF - 61st Annual Western Snow Conference T3 - Proceedings of the 61st Annual Western Snow Conference PB - Western Snow Conference CY - Quebec City, Quebec UR - sites/westernsnowconference.org/PDFs/1993Barry.pdf ER - TY - Generic T1 - Aerosol scavenging by falling snow T2 - 61st Annual Western Snow Conference Y1 - 1993 A1 - Cragin, J.H. A1 - Hewitt, A.D. KW - Crystals, Scavenging, Snowflakes AB - Removal of atmospheric aerosols by falling snow flakes was studied during several winters in Hanover, New Hampshire, using micrometer-sized particles. Experiments were performed in open air and within static and dynamic aerosol chambers. The primary scavenging mechanism for particles in this size range was inertial impaction. Scavenging efficiencies were determined by collecting and chemically analyzing snow flakes that were allowed to fall naturally through the static chamber containing a cloud of known aerosol concentration. The averaging scavenging efficiency (defined as the ratio of the mass of aerosol collected by the snow flake to the total mass of aerosol in the swept volume) of several different types of snow flakes and ice crystals was 0.11 ± 0.08. Higher scavenging efficiencies were observed for three-dimensional spatial dendrites than for planar crystals, such as planar dendrites and hexagonal plates. Overall, snow was found to be four to five times more efficient that rain in scavenging 0.3-to 6µm-sized particles. Laser attenuation measurements within a dynamic aerosol chamber indicated that particle scavenging can cause relative transmission increases of as much as 15% for each minute of exposure to snowfall. Model calculations predicted aerosol cloud half-lives of 2 to 20 minutes for snow precipitation rates of 2.5 to 0.5 cm/hr. JF - 61st Annual Western Snow Conference T3 - Proceedings of the 61st Annual Western Snow Conference PB - Western Snow Conference CY - Quebec City, Quebec UR - sites/westernsnowconference.org/PDFs/1993Cragin.pdf ER - TY - Generic T1 - Analysis of visible and microwave satellite data for snow mapping in Alaska T2 - 61st Annual Western Snow Conference Y1 - 1993 A1 - Hall, D.K. A1 - Benson, C.S. A1 - Chien, J.Y.L. KW - Microwaves, Passive microwaves, Radiometers, Satellite, Snow cover AB - Analysis of passive microwave Defense Meteorological Satellite Program (DMSP) Special Sensor Microwave Imager (SSMI) data, in conjunction with Advanced Very High Resolution Radiometer (AVHRR), topographic data and vegetation maps has been undertaken for a period of time in 1989 in Alaska. The combined use of visible, near-infrared and microwave sensors to map snow will lead to an improved ability to map snow extent, albedo and water equivalent. Such data are available now from the AVHRR, and in the future, from the Earth Observing System Moderate Resolution Imaging Spectroradiometer (MODIS). Passive microwave sensors are necessary in order to augment visible and near-infrared sensors which cannot acquire data through cloud cover and darkness. Results show a strong dependence of the microwave brightness temperature on topography, and land cover. Also, the influence of persistent meteorological conditions on snow temperature is hypothesized as an explanation for a brightness-temperature anomaly observed during the winter in the northern foothills of the Brooks Range, Alaska. JF - 61st Annual Western Snow Conference T3 - Proceedings of the 61st Annual Western Snow Conference PB - Western Snow Conference CY - Quebec City, Quebec UR - sites/westernsnowconference.org/PDFs/1993Hall.pdf ER - TY - Generic T1 - Associations between snow cover extent and surface air temperature over North America T2 - 61st Annual Western Snow Conference Y1 - 1993 A1 - Robinson, D.A. A1 - Leathers, D.J. KW - Climate change, Snow cover AB - We find significant associations between regional snow-cover extent and surface air temperature across North America. In a large majority of cases when the extent of snow cover is above normal, temperature departures are negative. Conversely, negative snow departures are almost always associated with above normal temperatures. Regional correlations are highest in seasons when snow cover is most variable. The largest temperature departures are associated with anomalies of snow cover over the central portion of the continent. An examination of 500 mb heights across North America suggests that – though circulation anomalies doubtlessly contribute to the temperature departures observed in regions of anomalous snow – the presence of absence of snow strongly influences temperatures. This relationship is most apparent in situations of above average snow extent. Results of this investigation should be of interest to those studying middle and high-latitude climate dynamics and climate change from both an empirical and modeling perspective. JF - 61st Annual Western Snow Conference T3 - Proceedings of the 61st Annual Western Snow Conference PB - Western Snow Conference CY - Quebec City, Quebec UR - sites/westernsnowconference.org/PDFs/1993Robinson.pdf ER - TY - Generic T1 - An automated quality control procedure for the water equivalent of snow on the ground measurement T2 - 61st Annual Western Snow Conference Y1 - 1993 A1 - Schmidlin, T.W. A1 - Wilks, D.S. A1 - Cember, R.P. KW - Errors, SWE AB - Snow water equivalent (SWE) has been measured daily by the United States National Weather Service since 1952 whenever show depth is 5 cm or greater. These data are used to develop design snow loads for buildings, for hydrological forecasting, and as an indicator of climate change, but have not been subjected to quality control. The quality control procedure developed here for the northeastern United States checks daily SWE measurements for common digitizing errors, values beyond reasonable limits, and consistency with daily precipitation and melt. Potential effects of drifting and the intrinsic micro-scale variability of SWE are also considered. A daily SWE measurement is declared suspicious if a sufficient discrepancy is found between the measurement and the expected SWE. Data flagged as errors are checked manually. JF - 61st Annual Western Snow Conference T3 - Proceedings of the 61st Annual Western Snow Conference PB - Western Snow Conference CY - Quebec City, Quebec UR - sites/westernsnowconference.org/PDFs/1993Schmidlin.pdf ER - TY - Generic T1 - Application of SAR snowcover mapping to hydrological modeling of snowmelt runoff in Southern Ontario T2 - 61st Annual Western Snow Conference Y1 - 1993 A1 - Seglenenieks, F. A1 - Soulis, E.D. A1 - Kouwen, N. A1 - Donald, J.R. KW - Modeling, Radar, Snow cover AB - In this experiment WATFLOOD, a distributed hydrologic model, was set up for the 1991 spring snowmelt event on the Grand River watershed to investigate the possibility of using airborne nadir C-band Synthetic Aperture Radar (SAR) imagery to update the model by providing snow covered area (SCA) information. WATFLOOD parameters were first derived using only atmospheric and ground data, the model was then run again to derive parameters using the SAR imagery to update the model. The results showed that model appeared to simulate the river flow better when updated using the SAR imagery. It was concluded that the present WATFLOOD optimization, which deals solely with river flows, allows for unrealistic values for snowmelt. This can be corrected by separate optimization of snowmelt parameters to known snow cover characteristics and of snowpack hydraulic characteristics to streamflow. JF - 61st Annual Western Snow Conference T3 - Proceedings of the 61st Annual Western Snow Conference PB - Western Snow Conference CY - Quebec City, Quebec UR - sites/westernsnowconference.org/PDFs/1993Seglenenieks.pdf ER - TY - Generic T1 - Applying a climatic change scenario to a semi-distributed watershed model T2 - 60th Annual Western Snow Conference Y1 - 1992 A1 - Kite, G. KW - Climate change, Watershed models AB - Atmospheric general circulation models (CGMs) predict major changes in the earth’s climate due to an expected doubling of atmospheric greenhouse gases such as CO2. Watershed models have been used to estimate the effects of the changed climate on water resources but these models have generally assumed that the watershed itself will remain unchanged. It is more likely that a changing climate will change the distribution and the transpiration efficiency of vegetation. A semi-distributed hydrological model was applied to a watershed in the Rocky Mountains of British Columbia. The watershed was divided into a number of sub-basins and each sub-basin was divided into land-use zones. The paper discusses the methods available for linking the output of the GCM to the watershed model and discusses the results of the application in terms of the model responses. JF - 60th Annual Western Snow Conference T3 - Proceedings of the 60th Annual Western Snow Conference PB - Western Snow Conference CY - Jackson Hole, Wyoming UR - sites/westernsnowconference.org/PDFs/1992Kite.pdf ER - TY - Generic T1 - Is April to July runoff really decreasing in the western United States T2 - 59th Annual Western Snow Conference Y1 - 1991 A1 - Wahl, K.L. KW - Annual runoff, Fractional runoff, Seasonal runoff, Trends AB - Several investigators have presented evidence that the ratio of April-July runoff to annual runoff has been decreasing in Western North America. The trend has been recognized both in rainfall-runoff and snowmelt-runoff streams. The decline in this ratio has been attributed to a change in the seasonal distribution of precipitation; there is concern that the changing ratio reflects a decrease in April-July runoff. Analysis of streamflow records for gaging stations that record natural flow confirms that the ratio has been declining at selected streamflow stations along the Pacific coast. The decline in the ratio, however, is by no means pervasive. Furthermore, tests for monotonic trend, while confirming a decline in the ratio, show no discernable trend in total April-July runoff, indicating that April-July runoff has not decreased. The trend in the ratio does appear to represent an increase in winter precipitation. JF - 59th Annual Western Snow Conference T3 - Proceedings of the 59th Annual Western Snow Conference PB - Western Snow Conference CY - Juneau, Alaska UR - sites/westernsnowconference.org/PDFs/1991Wahl.pdf ER - TY - Generic T1 - Assessing the effects of climate changes on snowpack and streamflow T2 - 57th Annual Western Snow Conference Y1 - 1989 A1 - Cooley, K.R. KW - Climate change, Runoff, Snowmelt AB - Projected increases in the atmospheric concentration of carbon dioxide could significantly change the earth's climate. Estimates of expected changes in temperature and precipitaion have been made by a number of researchers using theoretical models, empirical relationships, and actual long-term climatic data. The estimated changes range from warming the global surface temperatures by more than 4 degrees celsius, to cooling the surface temperature somewhat, and increasing or decreasing precipitation by about 10% in certain areas or regions of the world. In this sudy, the National Weather Service River Forecast System Model (NWSRFS) was used to estimate the effects of temperature and precipitation changes, of the magnitude suggested, on snowpack and streamflow for the Lower Willow creek Watershed, Montana, which is a predominately snowmelt-fed system. JF - 57th Annual Western Snow Conference T3 - Proceedings of the 57th Annual Western Snow Conference PB - Western Snow Conference CY - Fort Collins, Colorado UR - sites/westernsnowconference.org/PDFs/1989Cooley.pdf ER - TY - Generic T1 - Automated collection of water-quality and discharge data on streams T2 - 57th Annual Western Snow Conference Y1 - 1989 A1 - Sturges, D.L. A1 - Winter, C.J. KW - Automatic collection, Data loggers, Hydrologic investigations, Water stage AB -

The availability of relatively inexpensive electronic sensors for measuring water quality parameters and the availability of data loggers with low power requirements enable water-related data to be collected from remote sites at a reasonable cost. We present information about a system installed on a stream that collects information about water conductivity, pH, temperature, water stage, and air temperature. Information about sensor installation and calibration procedures, system maintenance tips, and samples of several data output formats are also presented.

JF - 57th Annual Western Snow Conference T3 - Proceedings of the 57th Annual Western Snow Conference PB - Western Snow Conference CY - Fort Collins, Colorado UR - sites/westernsnowconference.org/PDFs/1989SturgesA.pdf ER - TY - Generic T1 - Accuracy and repeatability of in situ snow wetness measurements using the newly developed twin-disc capacitance sensor T2 - 55th Annual Western Snow Conference Y1 - 1987 A1 - Bergman, J.A. KW - Accuracy, Capacitance, Measuring undisturbed snow, Snow wetness, Twin-disc sensor AB - If water from snowmelt and rain-on-snow can be tracked as it moves through the snowpack, streamflow forecasters could be informed of the potential for excessive snowpack outflow before actual outflow occurred and gain time to apply mitigation procedures to accommodate the extra water. During the winter of 1985-1986, eight twin-disc capacitance sensors, used to track changes in the liquid water content of snow (wetness) at the USDA Forest Service’s Central Sierra Snow Laboratory, in northern California, were calibrated and tested for their ability to repeat measurements. For all sensors, snow volume wetness varied less than 0.06%, indicating low 'between measurement' variability. To assess accuracy, twin-disc sensor wetness was compared with wetness measured by the Denoth-Fogler snow moisture meter. For all sensors, the difference between the measurement means of the two methods was 0.25% snow volume wetness. JF - 55th Annual Western Snow Conference T3 - Proceedings of the 55th Annual Western Snow Conference PB - Western Snow Conference CY - Vancouver, British Columbia UR - sites/westernsnowconference.org/PDFs/1987Bergman.pdf ER - TY - Generic T1 - Assessing landslide occurrence with snow data and other site information T2 - 55th Annual Western Snow Conference Y1 - 1987 A1 - Cheng, J.D. KW - Extreme Climatic Event, Landslides, Mass Wasting AB - In early April, 1985, large landslides occurred at several low elevation forested locations iN south central B.C. causing damage to railroad and fish habitats with economic and legal implications. The causes of these landslides were assessed using snow and temperature data as well as other site information. Field inspections revealed that several features combined to make these locations very susceptible to mass wasting. These features include steep and convergent slope, shallow soil with high density subsoil, and the evidence of scars from uprooted trees by previous windthrow. However, these landslides were considered to have been mainly triggered by an extraordinary climatic event that provided an extremely large amount of water to the soil. Analyses of snow course, snow pillow and temperature data indicate that this climatic event in fact produced record-breaking snowmelt water (380 mm) at these low elevation locations. JF - 55th Annual Western Snow Conference T3 - Proceedings of the 55th Annual Western Snow Conference PB - Western Snow Conference CY - Vancouver, British Columbia UR - sites/westernsnowconference.org/PDFs/1987Cheng.pdf ER - TY - Generic T1 - Acidic deposits and snowpack chemistry at a Sierra Nevada site T2 - 53rd Annual Western Snow Conference Y1 - 1985 A1 - Berg, N.H. A1 - Woo, S. KW - Acid snow, Acidification, Snowpack chemistry AB - Snowpack chemistry studies evaluated the fractionation model of rapid release of acidic pollutants from the snowpack near Donner Summit, California. Event samples of precipitation and snowpack basal outflow, and weekly samples of snowpit layers and stream water were analyzed for pH, alkalinity, and sulfate and nitrate solute concentrations. Chemical signatures from specific precipitation events identified subsequent changes in the chemistry of the snowpack and outflow waters. Acidification was not apparent in either stream or snowpack basal outflow waters during the main spring melt period. The lowest seasonal pH's for stream and basal outflow waters were, however, recorded synchronously with rain or mixed rain and snowfall precipitation events during early- and mid-winter when both basal outflows and stream discharges rose. Fractionation may bave caused these pH minima. Snowfall was slightly acidic at the test site, and mean pH for rainfall, hail, and graupel was below 5.0. Snowpack layer pH remained generally constant through time. JF - 53rd Annual Western Snow Conference T3 - Proceedings of the 53rd Annual Western Snow Conference PB - Western Snow Conference CY - Boulder, Colorado UR - sites/westernsnowconference.org/PDFs/1985Berg.pdf ER - TY - Generic T1 - Accuracy of hydrologic forecasts T2 - 53rd Annual Western Snow Conference Y1 - 1985 A1 - Dracup, J.A. A1 - Haynes, D.L. A1 - Abramson, S.D. KW - Accuracy, Forecasts AB - The analysis in this paper concentrates on the Colorado River Basin. Analyses of the correlations between forecasted and observed runoffs were made using Spearman rank-order coefficients, Product-Moment correlation coefficients, average forecast errors, and a derived statistical measure referred to as the Coefficient of Prediction. In addition, further statistical measures including the t-test were used. The analysis showed that even as early as January of each year worthwhile forecasts are being developed. The Coefficient of Prediction and the correlation coefficients compare favourably when used to judge which forecast stations had relatively higher forecast accuracy. The two statistical tests of correlation coefficients and Coefficients of Prediction are in agreement when analyzing the average forecast errors. These coefficients increase when the average forecast error decreases. The t-test proved to not be as good a measure to use when comparing different data sets. JF - 53rd Annual Western Snow Conference T3 - Proceedings of the 53rd Annual Western Snow Conference PB - Western Snow Conference CY - Boulder, Colorado UR - sites/westernsnowconference.org/PDFs/1985Dracup.pdf ER - TY - Generic T1 - Analysis of water supply forecast accuracy T2 - 53rd Annual Western Snow Conference Y1 - 1985 A1 - Schaake, J.C. Jr. A1 - Peck, E.L. KW - Accuracy, Error analysis, Forecasts AB - As part of a Federal interagency study to consider placing hydrometeorologic stations in wilderness areas of the Colorado River Basin, an analysis is being made of the factors contributing to errors in the forecasts. These factors include errors because of uncertainty in future climate (i.e. uncertainty in long-range weather events), limitations of data networks and limitations of forecast models. A statistical rationale is being developed to estimate these errors and to predict how these errors might be reduced by various improvements in data networks, models, and climate forecasts. This paper presents the early stages of development of the rationale and discusses the current status of the analytical methods being used. JF - 53rd Annual Western Snow Conference T3 - Proceedings of the 53rd Annual Western Snow Conference PB - Western Snow Conference CY - Boulder, Colorado UR - sites/westernsnowconference.org/PDFs/1985Schaake.pdf ER - TY - Generic T1 - Ablation rates of snow fence drifts at 2300-meters elevation in Wyoming T2 - 53rd Annual Western Snow Conference Y1 - 1985 A1 - Tabler, R. KW - Snow ablation, Snow density, Snow fences, Snowdrifts, Snowmelt AB - From April 10 to June 14, ablation rates of lee drifts behind 3.8-m-tall snow fences, having moderate bottom-gaps on level terrain, averaged about 1.0 cm/deg/day. Mean ablation rate was 11% greater for a fence having a 90-cm bottom-gap. Ablation rate averaged aboaut 5% more over the windward half of the lee drift as compared to the downwind half. This uniformity allows drift length, cross-sectional area, and potential melt rate to be predicted over the melt season.The Federal snow sampler overmeasured the density of melting drifts by about 10%. Although desity of drifted snow before melt varies with depth, melting snowdrifts have a uniform desity of about 600 kg/m3. JF - 53rd Annual Western Snow Conference T3 - Proceedings of the 53rd Annual Western Snow Conference PB - Western Snow Conference CY - Boulder, Colorado UR - sites/westernsnowconference.org/PDFs/1985Tabler.pdf ER - TY - Generic T1 - Analysis of 1983 snowmelt runoff production in the Upper Colorado river basin T2 - 52nd Annual Western Snow Conference Y1 - 1984 A1 - Shafer, B.A. A1 - Jensen, D.T. A1 - Jones, K.C. KW - Colorado flooding, SNOTEL, Snow cover, Snowmelt runoff, Streamflow forecasting AB - Spring and summer streamflow for 1983 was extraordinarily high in the Colorado River Basin as well as many others in the Western United States. Streamflow forecasts in these areas were low by from 30 to 100 percent. An investigation was undertaken to examine the hydrometeorological interactions that produced the unusually high runoff and caused such large errors. The synergistic interaction of snow water equivalent, snow areal extent, temperature, precipitation, and soil moisture were evaluated. SNOTEL data combined with satellite imagery were shown to be highly valuable in interpreting the sequence of events during the runoff period. Major causes for the extreme runoff are summarized and recommendations are made for improving forecast models to better predict future events of a similar nature. JF - 52nd Annual Western Snow Conference T3 - Proceedings of the 52nd Annual Western Snow Conference PB - Western Snow Conference CY - Sun Valley, Idaho UR - sites/westernsnowconference.org/PDFs/1984Shafer.pdf ER - TY - Generic T1 - Application of a snow water-equivalent prediction model to rain-on-snow events in the central Sierra Nevada T2 - 51st Annual Western Snow Conference Y1 - 1983 A1 - Berg, N.H. A1 - Hannaford, M.A. KW - Multiple regression, Prediction model, Snow water equivalent AB - Knowledge of snowpack water-equivalent is critical in evaluating the reaction of the snowpack to rainfall. Deep, high water-equivalent packs may retain some portion of the rainfall, while flood flows are more likely to result from rainfall on shallow, low water-equivalent packs. A regression model, involving 19 equations, has been developed for estimating real-time snowpack water-equivalent for locations within the American, Yuba and Mokelumne River basins of the central Sierra Nevada of California. The model yields multiple correlation coefficient values reaching 0.94. The equations use snowpack data from two manned hydrometeorological index stations and include information on site elevation, geographical coordinates, date and snowpack conditions at the index stations. Evaluation of the model during rain-on-snow conditions shows close agreement between predicted values and actual observations. JF - 51st Annual Western Snow Conference T3 - Proceedings of the 51st Annual Western Snow Conference PB - Western Snow Conference CY - Vancouver, Washington UR - sites/westernsnowconference.org/PDFs/1983Berg.pdf ER - TY - Generic T1 - Analysis of three rain on snow floods in the Sierra Nevada, California T2 - 51st Annual Western Snow Conference Y1 - 1983 A1 - Hall, R.L. A1 - Hannaford, J.F. KW - American River, Flood-hydrograph, Floods, Rain-on-snow, Sierra Nevada, Snow accumulation, Snowmelt AB - Historic rain on snow flood conditions were investigated during the design flood study for a project in the American River basin of California. Basins analyzed range in elevation from under 300 m to nearly 3000 m and have average annual precipitation between 1000 and 2000 mm. Proximity to the Central Sierra Snow Laboratory operated by the U.S. Forest Service and a first order National weather Service station provided temperature, dewpoint, radiation and wind data that allowed use of relatively detailed procedures for calculation of snow accumulation and melt. Watersheds were subdivided into contributing areas and snow condition was calculated for each area on an hourly basis. Rainfall and snowmelt runoff values from each area were routed through the stream channels. JF - 51st Annual Western Snow Conference T3 - Proceedings of the 51st Annual Western Snow Conference PB - Western Snow Conference CY - Vancouver, Washington UR - sites/westernsnowconference.org/PDFs/1983Hall.pdf ER - TY - Generic T1 - Application of a simple snowmelt-runoff model to large river basins T2 - 51st Annual Western Snow Conference Y1 - 1983 A1 - Rango, A. KW - Remote sensing, Snow cover, Snowmelt-runoff, User manual AB - The snowmelt-runoff model (SRM) developed by Martinec (1975) for use on small mountain basins (<50 sq km) has recently been extended to large river basins (200 -4000 sq km) using remotely-sensed snow-cover data. In addition to the snow-cover data obtained from satellites, the model only requires the input of daily temperature and precipitation data. For model operation, the following parameters must be determined: degree-day factor, runoff coefficient, recession coefficient, temperature lapse rate, and discharge time lag. Simple procedures allow use of SRM in a variety of conditions including rain on snow situations. The average absolute error between actual and simulted runoff volume for the snowmelt season for nine large basins was 3 percent. The average Nash-Sutcliffe R square value, which measures the daily flow fit, for the large basins was .85. In general, the simulation results tend to degrade as the quality of input data decreases which in most cases occurs as basin size increases. Techniques are currently being developed for using SRM in the forecast mode. To aid in application of SRM to a basin, a user manual is now available along with a sample data set for computer implementation. JF - 51st Annual Western Snow Conference T3 - Proceedings of the 51st Annual Western Snow Conference PB - Western Snow Conference CY - Vancouver, Washington UR - sites/westernsnowconference.org/PDFs/1983Rango.pdf ER - TY - Generic T1 - Application of airborne gamma radiation snow survey measurements and snow cover modeling in river and flood forecasting T2 - 49th Annual Western Snow Conference Y1 - 1981 A1 - Carroll, T.R. A1 - Larson, L.W. KW - Airborne snow survey, Flood forecasting, Gamma radiation, River forecasting, Snow melt modeling AB - The National Weather Service (NWS) has hydrologic forecasting reponsibilities for the United States. Two major technical procedures have recently been developed and implemented by the NWS to facilitate river and flood forecasting in large areas of the upper Midwest subject to extensive winter snow accumulation. First, a temperature based snow model is used to represent the physical processes associated with the accumulation and ablation of a snowpack and to simulate snow cover characteristics over much of the upper Midwest. Second, the implementation of an operational Airborne Gamma Radiation Snow Survey Program provides observed snow water equivalent data for large areas of the upper Midwest. A discussion of the snow accumulation and ablation model and its application to the NWS River Forecasting Procedure is given. In addition, the theory, application, capability, and limitation of the airborne gamma radiation attenuation technique are discussed. JF - 49th Annual Western Snow Conference T3 - Proceedings of the 49th Annual Western Snow Conference PB - Western Snow Conference CY - St. George, Utah UR - sites/westernsnowconference.org/PDFs/1981Carroll.pdf ER - TY - Generic T1 - Application of a snowmelt model to two drainage basins in Colorado T2 - 49th Annual Western Snow Conference Y1 - 1981 A1 - Jones, E.B. A1 - Shafer, B.A. A1 - Rango, A. A1 - Frick, D.M. KW - Landsat imagery, Runoff, Snowcovered area, Snowmelt runoff AB - The Martinec-Rango Snowmelt Model has evolved over a period of years from one that was developed for a relatively small drainage to its current application on much larger areas. The input requirements for the model include the remotely sensed percentage of snow-covered areas within the limits of the watershed, daily temperature, and precipitation. All of these data can be input on a multi-zonal basis.The current project analyzed the use of this model on the South Fork of the Rio Grande River (559 km sq) and on the Conejos River above Magote (730 km sq). Both of these watersheds are larger than had previously been considered for use with this model. The simulated volume of runoff versus the actual runoff were within 1 to 12 percent for the 6-month snowmelt period. Nash-Sutcliffe `R squared' values for daily runoff simulations exceeded 0.88 in all years except the very dry year of 1977. JF - 49th Annual Western Snow Conference T3 - Proceedings of the 49th Annual Western Snow Conference PB - Western Snow Conference CY - St. George, Utah UR - sites/westernsnowconference.org/PDFs/1981Jones.pdf ER - TY - Generic T1 - Areal determination of the influence of a forest canopy on the surface radiant energy exchange T2 - 48th Annual Western Snow Conference Y1 - 1980 A1 - Marks, B. A1 - Marks, D. KW - Alpine climatology, Remote sensing AB - To accurately model the energy balance of an alpine snowpack, the influence of a vegetation canopy on the surface radiant energy exchange must be known. A number of studies have been conducted to determine the shading effects of a canopy at a point. This paper presents a new method of estimating canopy cover density which can be extended over a large area. Canopy shading functions, developed from photographic techniques, describe the proportion of the hemisphere surrounding a point which is partially obscured by vegetation. A general diffuse shading function and a beam shading function which account for changes in solar zenith are presented. Both functions account for changes in canopy cover density with variations in snow depth. The technique presented is to be modified and tested during summer, 1980, so that it can utilize Landsat satellite data to determine canopy densities over a large area. The shading functions can then be used in areal models of solar and terrestrial radiation. JF - 48th Annual Western Snow Conference T3 - Proceedings of the 48th Annual Western Snow Conference PB - Western Snow Conference CY - Laramie, Wyoming UR - sites/westernsnowconference.org/PDFs/1980Marks.pdf ER - TY - Generic T1 - Application of meteor burst telemetry to snow hydrology T2 - 47th Annual Western Snow Conference Y1 - 1979 A1 - Burroughs, H.F. A1 - Patterson, P.E. KW - Telemetering equipment AB - With the successful implementation of two hydrometeorological data acquisition systems using meteor burst technology during 1978, a review of associated capabilities and limitations is appropriate for the purpose of evaluating the potential of such systems for other planned automations.Data transmission via ionized trails in the upper atmosphere is accomplished by means of specially designed equipment configured in a network consistent with the survey requirement, radio path characteristics, and site conditions. The equipment must provide for a proper power budget, appropriate antenna arrays, capabilities for RF analog signal processing, data handling through digital logic circuits, and flexible sensor interface logic. A well designed software package is required to effectively control and command the system and to collect, organize, and forward sensor data. JF - 47th Annual Western Snow Conference T3 - Proceedings of the 47th Annual Western Snow Conference PB - Western Snow Conference CY - Sparks, Nevada UR - sites/westernsnowconference.org/PDFs/1979Burroughs.pdf ER - TY - Generic T1 - Application of snowcovered area to runoff forecasting in the southern Sierra Nevada T2 - 47th Annual Western Snow Conference Y1 - 1979 A1 - Hannaford, J.F. A1 - Hall, R.L. A1 - Brown, A.J. KW - Aerial measurement, Models-snowmelt, Photographic measurement, Snow measurement, Water supply forecasting AB -

Long-term snowcovered area data from aircraft and satellite observation made it possible to analyze the effect of snowcovered area on water supply forecasting procedures in California's southern Sierra Nevada. Water supply forecasting procedures utilizing snowcovered area as a parameter were developed on the Kings River and Kern River under the sponsorship of the California Department of Water Resources and NASA. 1978 was the first season with major snowmelt runoff since the procedures were developed, and snowcovered area was used operationally in making and updating the forecast through the period of snowmelt runoff.The forecast procedures developed for the Kern River did show a substantial reduction in error as the season progressed. Results were far from dramatic on the Kings. During 1978 a series of storms throughout the winter with extremely high freezing levels produced snowpack in the order of 200 percent of normal at higher elevations. The relatively high snow lines and lighter snowpack at the lower elevations were not consistent with snowpack at upper elevations.

JF - 47th Annual Western Snow Conference T3 - Proceedings of the 47th Annual Western Snow Conference PB - Western Snow Conference CY - Sparks, Nevada UR - sites/westernsnowconference.org/PDFs/1979HannafordA.pdf ER - TY - Generic T1 - Automatic hydrometeorological telemetry network of Alberta T2 - 46th Annual Western Snow Conference Y1 - 1978 A1 - Graham, D.R. A1 - Kerr, W.E. A1 - Grauman, R.J. KW - Hydrologic data, Telemetering data AB - The planning of the Alberta Environment remote telemetry system began in 1974 and the first precipitation remotes were installed in early 1976. This system was designed to support four distinct subsystems: a) Air quality Monitoring Subsystem, b) Water Quality Monitoring Subsystem, c) Water Level Monitoring Subsystem, d) Water Level and Precipitation Subsystem. All of the Precipitation Subsystem and most of the Water Level Subsystem was designed and built by local firms to operate in extreme environment conditions. The specifications for the precipitation remotes stated that the equipment must operate in an environment between -40 degrees C and +55 degrees C, with relative humidities up to 99%. There are three distinct parts to the system. a) Automatic Collection of the Data; b) Transmission of the Collected Data; c) Receiving, Storing and Editing Data. The intention of this paper is to outline the system showing its present and future capabilities. JF - 46th Annual Western Snow Conference T3 - Proceedings of the 46th Annual Western Snow Conference PB - Western Snow Conference CY - Otter Rock, Oregon UR - sites/westernsnowconference.org/PDFs/1978Graham.pdf ER - TY - Generic T1 - Acoustic emissions in the investigation of avalanches T2 - 45th Annual Western Snow Conference Y1 - 1977 A1 - Bowles, D. A1 - St. Lawrence, W. KW - Avalanche research, Research ice and snow, Settlement of snowpack, Snow avalanche research AB - This paper reports on the results of several years of investigations into the role of ultrasonic emissions in the deformation and failure process in snow. The origin of ultrasonic emissions in snow is discussed and the manner in which these emissions enter tnto the process of deformation is considered. The results of several laboratory experiments are presented. In the laboratory acoustic emission investigations were conducted in a frequency range from 30 KHZ to 300 KHZ. Snow samples were subjected to various load and deformation histories and the acoustic response recorded. Laboratory investigations were also conducted to study the pattern of acoustic activity as it relates to the failure properties of snow.In the field, a two-year investigation was conducted to determine if the acoustic patterns observed under laboratory conditions would also appear in natural snow slopes. This study indicated that although the acoustic activity is not as well defined in situ, certain patterned responses are detected which relate to developing stability and instability in the snow pack. JF - 45th Annual Western Snow Conference T3 - Proceedings of the 45th Annual Western Snow Conference PB - Western Snow Conference CY - Albuquerque, New Mexico UR - sites/westernsnowconference.org/PDFs/1977Bowles.pdf ER - TY - Generic T1 - The avalanche warning program in Colorado T2 - 45th Annual Western Snow Conference Y1 - 1977 A1 - Judson, A. KW - Avalanche warning AB - Avalanche warnings for Colorado originate from the Forest Service's Rocky Mountain 'Forest and Range Experiment Station in Fort Collins. The current program, which began on an informal basis in 1962, has been operating formally as a joint venture with the National Weather Service since 1973. More than 150 avalanche warning bulletins have been issued during the past 3 winters. The warnings cover part or all of the State's high mountains west of the 105th meridian. Principle components of the warning system include a network of 55 mountain reporting sites, custom made mountain weather forecasts that feature predicted quantitative precipitation amounts from an orographic precipitation model, an avalanche warning center, and a communications system for disseminating avalanche warnings to the public. The program, now in its fourth winter, is running smoothly. Warnings have been well received by the public, and response has been good. Development of danger-rating models and fine tuning of the newly developed orographic precipitation model for the Colorado mountains will continue to aid the warning program. JF - 45th Annual Western Snow Conference T3 - Proceedings of the 45th Annual Western Snow Conference PB - Western Snow Conference CY - Albuquerque, New Mexico UR - sites/westernsnowconference.org/PDFs/1977Judson.pdf ER - TY - Generic T1 - The application of aerial and satellite snow-mapping techniques for multi-purpose reservoir system operations in Arizona T2 - 45th Annual Western Snow Conference Y1 - 1977 A1 - Kirdar, E. A1 - Schumann, H.H. A1 - Warskow, W.L. KW - Mapping photography satellite, Snow cover photo mapping, Snow measurement AB - Multipurpose reseroir system operations in central Arizona requires timely and dependable snowmelt information. This requirement led to aerial snow-mapping on the Salt and Verde watersheds in late 1965. Snow maps have proven to be a valuable decision-making tool for system operations. The maps have also been used in verification and improvement of satellite snow-mapping technique which was successfully applied by the Salt River Project during the 1975-76 runoff season under the NASA-ASVT program. Preliminary hydrologic analysis of snowmelt runoff is being made. Timely satellite snowpack information is being integrated into the decision-makeing process for multi-purpose reservoir system operations in Arizona. JF - 45th Annual Western Snow Conference T3 - Proceedings of the 45th Annual Western Snow Conference PB - Western Snow Conference CY - Albuquerque, New Mexico UR - sites/westernsnowconference.org/PDFs/1977Kirdar.pdf ER - TY - Generic T1 - Application of a new hydrometeorological streamflow prediction model T2 - 45th Annual Western Snow Conference Y1 - 1977 A1 - Tangborn, W.V. KW - Precipitation data forecasting, Water supply forecasting with prec data AB - A mathematical model to predict seasonal streamflow, using only low-altitude precipitation gages and streamflow gaging stations, is described. The main features of the model developed are: (1) It can be implemented in any basin that has a large snow storage component, historical streamflow records, and precipitation observations in or near the basin. (2) It is based on simple but rational premises: that basin storage is approximately equal to winter precipitation minus winter runoff, that the catch of a low-altitude precipitation gage is proportional to nearby upland precipitation, and that storage is eventually released as summer streamflow. (3) It does not require expensive high-altitude installations to obtain data. (4) It incorporates a method to test and revise the estimate of storage available for release as summer streamflow.Tests of the model to obain retrospective predictions for the past 10 to 15 years are shown for basins in the North Cascades of Washington, the South Central Sierra Nevada, and for Norway. These tests show that the model appears to be about 20 percent more accurate than existing methods. JF - 45th Annual Western Snow Conference T3 - Proceedings of the 45th Annual Western Snow Conference PB - Western Snow Conference CY - Albuquerque, New Mexico UR - sites/westernsnowconference.org/PDFs/1977Tangborn.pdf ER - TY - Generic T1 - Avalanche zoning: current status, obstacles and future needs T2 - 45th Annual Western Snow Conference Y1 - 1977 A1 - Tesche, T.W. KW - Avalanche zoning AB - The rapid expansion of winter recreational facilities, housing subdivisions, highways, mining operations and energy lifelines into mountainous areas has dramatically increased the frequency of man's exposure to avalanche disaster. Currently, the limitations of access to hazardous areas during periods of high danger and control over the construction of structures in hazardous areas are the most promising means of mitigating avalanche hazards. This paper focuses upon land use zoning regulations pertaining to avalanche hazard and the need for expanded zoning efforts in the Western United States.With the exception of the State of Colorado, avalanche zoning in the United States, where it exists at all, is piecemeal and fragmented. The general lack of consistent land use policy for natural hazard areas, particularly avalanche areas, stems from complex interactions between local socioecomomic, legal and political pressures. Confounding the avalanche zoning problem are current scientific problems in delimiting the snow avalanche hazard, improving hazard recognition, estimating destruction potential and encounter probabilities, and avalanche zone mapping. JF - 45th Annual Western Snow Conference T3 - Proceedings of the 45th Annual Western Snow Conference PB - Western Snow Conference CY - Albuquerque, New Mexico UR - sites/westernsnowconference.org/PDFs/1977Tesche.pdf ER - TY - Generic T1 - The application of isotopic profiling snow gauge data to avalanche research T2 - 44th Annual Western Snow Conference Y1 - 1976 A1 - Armstrong, R.L. KW - Avalanche research, Radioactive snow gauges, Snow gauges AB - The Institute of Arctic and Alpine Research (INSTAAR), University of Colorado, has been conducting research into the nature and causes of snow avalanches in the San Juan Mountains of southwestern Colorado. An isotopic profiling snow gauge has been operated in conjunction with the research during five winter seasons. Specifications and a brief history of the development of the two types of gauges which have been operated at the Red Mountain Pass snow study site are presented.The structure of the existing snowcover and the amount and rate of additional new snow accumulation are of critical importance in avalanche studies. Conventional methods for acquiring this tpe of information are compared with data available from the profiling snow gauge. Additional data analysis relating to the study of the physical and mechanical properties of snow is presented. Techniques regarding the location, installation and operation of a profiling snow gauge for avalanche forecasting and research are discussed. JF - 44th Annual Western Snow Conference T3 - Proceedings of the 44th Annual Western Snow Conference PB - Western Snow Conference CY - Calgary, Alberta UR - sites/westernsnowconference.org/PDFs/1976Armstrong.pdf ER - TY - Generic T1 - Areal water equivalents for prairie snowcovers by centralized sampling T2 - 44th Annual Western Snow Conference Y1 - 1976 A1 - Steppuhn, H. KW - Snow cover analysis AB - Accurate estimates of water quantities stored as snow covering prairie lands can improve runoff forecasting and agricultural management. Centralized sampling offers an efficient shortcut for determining mean, error-qualified, areal water equivalents in shallow snowcovers. This method reduces sample size and retains accuracy (1) by exploiting the close relationship between rural landscapes and snowcover distribution, (2) by separating sampling for snow depth from sampling for verical density, and (3) by sampling for density selectively based on a central depth statistic. Snow data for 1972-75 from 23 areal landscapes in Saskatchewan showed that reducing sample numbers by 1/5 or less resulted in average deviation from the mean areal density of 3.3, 3.1, or 4.8% for the mean, mode,and median depth statistic, repectively. Centralized sampling will comlement any snow meaurement technique, including ground-based tube-coring and serial gamma-sensing. JF - 44th Annual Western Snow Conference T3 - Proceedings of the 44th Annual Western Snow Conference PB - Western Snow Conference CY - Calgary, Alberta UR - sites/westernsnowconference.org/PDFs/1976Steppuhn.pdf ER - TY - Generic T1 - Airflow patterns and snow accumulation in a forest clearing T2 - 43rd Annual Western Snow Conference Y1 - 1975 A1 - Gary, H.L. KW - Drifting snow, Snow cover in forests, Snow transport distance AB - Snow accumulation and airflow patterns were measured before and after establishing a clearing 1 tree-height wide and 5 tree-heights long in a lodgepole pine forest. The long axis was normal to prevailing wind. The profile of accumulated snow, less the mean amount of snow upwind of the clearing, was compared with the streamline patterns of airflow. Snow profiles are shown for 2 years where annual accumulation varied by a factor of 2. Snow accumulation was maximum in the clearing and minimum just behind the lee clearing edge. The maximum was centered about the upwind edge of the back eddy of airflow in the clearing. The minumum coincided with the down wind edge of the same eddy. These comparisons suggest that clearings may become saturated similar to snowfence systems, and that the accumulation pattern reflects primarily wind drift of falling snow rather than subsequent erosion and redeposition. JF - 43rd Annual Western Snow Conference T3 - Proceedings of the 43rd Annual Western Snow Conference PB - Western Snow Conference CY - Coronado, California UR - sites/westernsnowconference.org/PDFs/1975Gary.pdf ER - TY - Generic T1 - Automated remote data acquisition T2 - 43rd Annual Western Snow Conference Y1 - 1975 A1 - Horton, D.D. KW - Telemetering hydrologic data AB - Automation of remote data collection sites is now possible, due to reliable solid state components and other technical advances. This paper presents a methodology for determining the optimum components comprising an automated remote data acquisition system from the currently available alternatives. JF - 43rd Annual Western Snow Conference T3 - Proceedings of the 43rd Annual Western Snow Conference PB - Western Snow Conference CY - Coronado, California UR - sites/westernsnowconference.org/PDFs/1975Horton.pdf ER - TY - Generic T1 - Accuracy of snow measurements T2 - 43rd Annual Western Snow Conference Y1 - 1975 A1 - Peterson, N.R. A1 - Brown, A.J. KW - Sampling accuracy tests, Snow sampling AB - Investigation of snow measurement accuracy has been conducted by the California Cooperative Snow Survey Program at the Alpha Instrument Evaluation Site since 1965. Results of volumetric tests conducted at the site to determine snow sample tube accuracy are presented. A method to adjust manual control samples at operational automatic snow sensors in order to check telemetered data accuracy is outlined. Application of correction factors, derived from these studies, is illustrated. An adopted operational program for obtaining scheduled control samples at field sites in California is explained. JF - 43rd Annual Western Snow Conference T3 - Proceedings of the 43rd Annual Western Snow Conference PB - Western Snow Conference CY - Coronado, California UR - sites/westernsnowconference.org/PDFs/1975Peterson.pdf ER - TY - Generic T1 - Airflow and gas exchange in snow-fact or fiction T2 - 43rd Annual Western Snow Conference Y1 - 1975 A1 - Van Haveren, B.P. KW - Snow water vapor, Snow water vapor movement AB - Snow physicists have paid little attention to the topics of airflow phenomena, void air composition, and gas transfer mechanisms in the seasonal snowpack. These processes have both hydrologic and biologic significance. Although recent information has been gathered on the concentrations and transfer characteristics of water vapor in s snow, these studies need to be expanded and intensified. The results from these preliminary studies appear to indicate that water vapor moves within and from the snowpack by diffusion and also by convection, and that concentrations of water vapor in the voids of surface snow layers may be strongly influenced by atmospheric conditions at the snow surface. Biological activity under the spring snowpack increases as snow and soil temperatures increase. Most of this activity is concentrated at or within a few centimeters of the soil-snow-interface. In order for organisms to survive under these conditions, the processes of photosynthesis and respiration must occur, which necessarily involves exchange of CO2 and O2. JF - 43rd Annual Western Snow Conference T3 - Proceedings of the 43rd Annual Western Snow Conference PB - Western Snow Conference CY - Coronado, California UR - sites/westernsnowconference.org/PDFs/1975Van Haveren.pdf ER - TY - Generic T1 - Avalanche studies in the San Juan mountains of southwestern Colorado T2 - 41st Annual Western Snow Conference Y1 - 1973 A1 - Armstrong, R.L. KW - Avalanche, Physical properties, Project skywater, Statistical evaluation AB - This publication contains an overview of the snow avalanche research activities being conducted by the Institute of Arctic and Alpine Research, University of Colorado, in the San Juan Mountains of Southwestern Colorado. The research is funded by the U.S. Bureau of Reclamation with the objective being to develop a forecast model for avalanche occurrence in an area of the San Juan Mountains being considered as a possible target area for the cloud seeding operations of Project Skywater. The field methods being used to acquire data regarding avalanche occurrence are described. In addition, research directed towards establishing an Avalanche Zoning Plan for San Juan County and the town of Silverton is described. JF - 41st Annual Western Snow Conference T3 - Proceedings of the 41st Annual Western Snow Conference PB - Western Snow Conference CY - Grand Junction, Colorado UR - sites/westernsnowconference.org/PDFs/1973Armstrong.pdf ER - TY - Generic T1 - Avalanche awareness and safety for snow scientists in the field T2 - 40th Annual Western Snow Conference Y1 - 1972 A1 - Hotchkiss, William R. KW - Avalanche safety AB - During the winter of 1970-71, avalanches in the United States caught 58 people, buried 46, and killed 12. Snow scientists should periodically update their knowledge of how to classify avalanche events and to evaluate avalanche hazards. A practical, three-part classification of avalanches is proposed. Part I includes static observations made following the event; Part II includes dynamic observations made at the time of the event; and Part III includes genetic deductions based on a description of the meteorological background,. Evaluation of hazard is possible through careful observation of the definitive factors which cause avalanches; accumulation of new-fallen and wind-transported snow, free water percolation through the snowpack, and progressive weakening of internal layers of the snowpack. Knowledge of avalanche classification and hazard evaluation together with the use of sound judgement, should promote avalanche awareness and safety. JF - 40th Annual Western Snow Conference T3 - Proceedings of the 40th Annual Western Snow Conference PB - Western Snow Conference CY - Phoenix, Arizona UR - sites/westernsnowconference.org/PDFs/1972Hotchkiss.pdf ER - TY - Generic T1 - The application of snowmelt forecasting to combat Columbia River nitrogen supersaturation problem T2 - 40th Annual Western Snow Conference Y1 - 1972 A1 - Speers, D.D. KW - Model, Reservoir regulation, Runoff, Simulation, Snowmelt AB - The problem of nitrogen supersaturation on the Columbia River which is alleged to have resulted in severe fisheries losses, is discussed. The cause of nitrogen supersaturation and its effect on fish are reviewed, and several structural solutions to the problem are presented. An effective means in reducing the problem lies in the regulation of upstream reservoirs, and snowmelt forecasting plays an important role in this regulation. Two types of forecasts are utilized, volumetric forecasts determined by multiple regression procedures, and daily simulation of runoff using the SSARR computer model. These procedures are briefly described and examples of their application in combating the nitrogen supersaturation problem are given. JF - 40th Annual Western Snow Conference T3 - Proceedings of the 40th Annual Western Snow Conference PB - Western Snow Conference CY - Phoenix, Arizona UR - sites/westernsnowconference.org/PDFs/1972Speers.pdf ER - TY - Generic T1 - Air temperature observations and forecasts - their relationship to the prediction of spring snowmelt in the Eagle River Basin, Colorado T2 - 40th Annual Western Snow Conference Y1 - 1972 A1 - Zimmerman, A.L. KW - Runoff, Snowmelt, Temperature index, Water supply forecasts AB - A simple temperature index to snowmelt based on daily maximum temperature, performs quite well in the Eagle River Basin In Colorado in the spring snowmelt season during clear-weather melt conditions. During weather situations where a significant change of air mass is occurring, air temperatures are likely to be a poorer index to snowmelt than during relatively stable, dry periods. Therefore, additional air temperature data for a given river basin might not significantly improve snowmelt prediction during such periods. The predictability of air temperatures in a time frame of the next several days is improving as the general circulation prognoses improve. JF - 40th Annual Western Snow Conference T3 - Proceedings of the 40th Annual Western Snow Conference PB - Western Snow Conference CY - Phoenix, Arizona UR - sites/westernsnowconference.org/PDFs/1972Zimmerman.pdf ER - TY - Generic T1 - Advanced techniques overcome severe environment encountered by mobile communications system T2 - 39th Annual Western Snow Conference Y1 - 1971 A1 - Gornall, J.C. KW - Instrumentation, Telemetering equipment, Telemetering hydrologic data AB - For many years, radio engineers have sought to overcome severe environmental conditions encountered in remote mountainous areas and have dreamed of a radio station which would require no access roads, no power lines, no battery charging, and after a quick, easy and economical installation, would provide extremely high reliability and require no attention for at least five years. This dream evidently has been realized in British Columbia by the development of the special VHF radio stations described in this paper. The presentation of the paper included a series of eighty colored slides illustrating the historical background of the development, a description of the radio station equipment as well as some field installations of mountain top repeaters and snow course base stations. JF - 39th Annual Western Snow Conference T3 - Proceedings of the 39th Annual Western Snow Conference PB - Western Snow Conference CY - Billings, Montana UR - sites/westernsnowconference.org/PDFs/1971Gornall.pdf ER - TY - Generic T1 - An approach to snow load evaluation T2 - 38th Annual Western Snow Conference Y1 - 1970 A1 - Brown, J.W. KW - Snow load evaluation AB - The development of the 1964 Washoe County, Nevada, Snow Load Code is presented. Comparison is made with the 1965 National Building Code of Canada, together with comments indicating the general applicability of same to other regions. A general method of evaluating snow load values is outlined, including consideration of recurrence interval. Recommendations for additional snow courses in urbanizing mountainous areas for correlation to longer term stations are set forth. JF - 38th Annual Western Snow Conference T3 - Proceedings of the 38th Annual Western Snow Conference PB - Western Snow Conference CY - Victoria, British Columbia UR - sites/westernsnowconference.org/PDFs/1970Brown.pdf ER - TY - Generic T1 - The automatic hydrological radio reporting network New England division, Corps of Engineers T2 - 38th Annual Western Snow Conference Y1 - 1970 A1 - Gray, C.H. KW - Flood warning network, Telemetering hydrologic data AB -

As an integral part of a comprehensive plan of protection from flood hazards in New England area, the Corps of Engineers has designed an automatic data collection network. This radio operated network provides extensive hydrologic data including river, reservoir and tide levels, wind velocity and direction, barometric pressure and precipitation levels in five major New England river basins. At the central station the reporting network is interfaced directly with an IBM 1130 which can automatically interrogate the entire system and provides a complete printout in three minutes.

JF - 38th Annual Western Snow Conference T3 - Proceedings of the 38th Annual Western Snow Conference PB - Western Snow Conference CY - Victoria, British Columbia UR - sites/westernsnowconference.org/PDFs/1970GrayA.pdf ER - TY - Generic T1 - Aerial photographs for operational streamflow forecasting in the Colorado Rockies T2 - 37th Annual Western Snow Conference Y1 - 1969 A1 - Leaf, C.F. KW - Ablation, Aerial photographs, Water supply forecasting AB - A method is developed for predicting and simulating the snowmelt runoff hydrograph by using aerial photographs taken vertically, then measuring, piece-meal, the percent of the basin covered with snow on the total basin. The procedure is developed by means of empirical correlations between snow cover depletion and runoff. In addition the application is made to daily simulation of streamflow depletion-runoff relationship and can be used effectively as a basis for advanced estimates of residual volume of flow during the remainder of the snowmelt season. Photographs are taken at about 10 day intervals, with a scale of 500 feet to the inch. The confines of the basin are divided into elevation zones and totals are derived from tabulations where the snow cover depletions are summarized. Relationships between the several variables are determined by multiple regression correlations solved by electronic computer procedures. JF - 37th Annual Western Snow Conference T3 - Proceedings of the 37th Annual Western Snow Conference PB - Western Snow Conference CY - Salt Lake City, Utah UR - sites/westernsnowconference.org/PDFs/1969Leaf.pdf ER - TY - Generic T1 - Alaska telemetering network for the Corps of Engineers and the U. S. Weather Bureau T2 - 36th Annual Western Snow Conference Y1 - 1968 A1 - Gray, C.H. KW - Flood warning network, Telemetering equipment AB - After the disastrous flood at Fairbanks, Alaska in August 1967 a flood warning system was designed and put into operation, to prevent future disasters. Studies were made of causes and sufficient remote operation electronic equipment was selected to make an efficient network of stations. The Chena and Tanana Rivers were instrumented with telemetering equipment. Stream gages for river height and temperature electronic thermometers, snow gages, all instruments were automatic and synchronized electronically for base stations and repeater stations connecting Fairbanks and Anchorage offices. All electronic equipment is of the latest solid state design, with plug-in modules for easy repair by non technical personnel. Schematic drawings show the locations of stations and necessary telemetering and repeater stations. JF - 36th Annual Western Snow Conference T3 - Proceedings of the 36th Annual Western Snow Conference PB - Western Snow Conference CY - Lake Tahoe, Nevada UR - sites/westernsnowconference.org/PDFs/1968Gray.pdf ER - TY - Generic T1 - The area of maximum effect resulting from the Lake Almanor randomized cloud seeding experiment T2 - 36th Annual Western Snow Conference Y1 - 1968 A1 - Mooney, M.L. A1 - Lund, G.W. KW - Cloud seeding, Cloud seeding effectiveness, Cloud seeding evaluation, Weather modification AB - A randomized cloud seeding experiment was conducted on the Lake Almanor watershed near Mt. Lassen, California, during five winter seasons, 1962-67. The target area extended approximately 20 miles east-west and 15 miles north-south, and ranged in elevation from 4,500 to 6,400 feet, MSL. Silver iodide was released from ground based acetone solution generators which were located between 6,000 and 7,400 feet, MSL. Silver iodide releases were made for 12 hour periods and these periods were subsequently divided into four weather categories, three of which together produced approximately 85% of the total precipitation, no response to the seeding was observed in the target area. In the remaining category, characterized by westerly winds and cold temperatures, the increase peaked at approximately 59% between 5 and 11 miles downwind, and averaged 27% throughout the 21 mile distance. Both results were statistically significant at the 5% level. JF - 36th Annual Western Snow Conference T3 - Proceedings of the 36th Annual Western Snow Conference PB - Western Snow Conference CY - Lake Tahoe, Nevada UR - sites/westernsnowconference.org/PDFs/1968Mooney.pdf ER - TY - Generic T1 - Atmospheric water resources of the Wasatch Front, Utah T2 - 35th Annual Western Snow Conference Y1 - 1967 A1 - Fletcher, J.E. KW - Project skywater, Weather modification AB - An outline is presented, for research of weather modification experiments along the Wasatch Front, Utah. The objectives are briefly stated: 1) to determine the feasibility of increasing water supplies by cloud seeding; 2) to develop more effective methods of cloud seeding; 3) to develop better equipment and methods of evaluation the effectiveness of cloud seeding; 4) to evaluate and delineate the area affected by cloud seeding under different synoptic conditions and generator placement locations; 5) to determine the unique characteristics of storm systems; and 6) to make the best possible estimate of the efficiency of precipitation mechanisms associated with these storms. experimental work to be carried on relative to systems of telemetering of hydrologic data from various sensing equipment is planned. New types of silver iodide generators are planned and an evaluation as compared with older types. JF - 35th Annual Western Snow Conference T3 - Proceedings of the 35th Annual Western Snow Conference PB - Western Snow Conference CY - Boise, Idaho UR - sites/westernsnowconference.org/PDFs/1967Fletcher.pdf ER - TY - Generic T1 - Atmospheric water resources research summer hydrology of the high Sierra T2 - 35th Annual Western Snow Conference Y1 - 1967 A1 - Hannaford, J.F. A1 - Williams, M.C. KW - Hydrology flow analysis AB - A Progress report is presented for a hydrologic study dealing with the runoff produced by summer precipitation over the High Sierra, from the Kern River Basin north through the Mokelumne River basin. This study was necessary to complete the knowledge of the hydrologic cycle for the runoff from the Central Sierra Nevada Mountains western slope. Data are presented of precipitation and runoff data from gaging stations as shown. Runoff analysis is shown graphically covering some 35 stations for a period of 25 years, 1940-64. The time period of the year ran from the end of snowmelt to the beginning of each snow season. Items covered are: hydrograph characteristics; volume of runoff; timing; storm characteristics; and precipitation values. All items are discussed in the text of the paper. JF - 35th Annual Western Snow Conference T3 - Proceedings of the 35th Annual Western Snow Conference PB - Western Snow Conference CY - Boise, Idaho UR - sites/westernsnowconference.org/PDFs/1967Hannaford.pdf ER - TY - Generic T1 - Application of radar to snow surveying T2 - 33rd Annual Western Snow Conference Y1 - 1965 A1 - Grant, L.O. A1 - Marwitz, J.D. A1 - Thompson, C.W. KW - Radar, Snowpack measurements AB - Many problems exist in the use of radar for snow surveying and considerable research is being carried on in several countries. However at the present time many valuable factors can be measured and are described: onset time ; duration; intensity with time; direction of movement; rate of movement variation with the snow area; total snowfall and probably some information on size and shape of particles. With most equipment currently available, the maximum usable range for most snowfalls of the type experienced in the Rockies is in the range of 5 to 10 miles. Scope integration techniques are available to integrate accumulations over moderate sized watersheds. Radar can be particularly valuable in determining the representativeness of spot snow tube or pillow observations. Radar can also provide a unique tool for summarizing the rate of accumulation at all stages of snowpack developments. Formula development and data are shown in the text. JF - 33rd Annual Western Snow Conference T3 - Proceedings of the 33rd Annual Western Snow Conference PB - Western Snow Conference CY - Colorado Springs, Colorado UR - sites/westernsnowconference.org/PDFs/1965Grant.pdf ER - TY - Generic T1 - Avalanche control on highways T2 - 31st Annual Western Snow Conference Y1 - 1963 A1 - Atwater, M.M. KW - Avalanche control, Avalanche research AB - A summarization of avalanche control needs and procedures for structures, winter sports areas and trans-mountain highways is presented. A description of a high altitude mining company avalanche control program is included. Comparisons of protection procedures are made and the economics of costs versus benefits derived are analyzed. Five elements of avalanche control are outlined and applied to practical problems. JF - 31st Annual Western Snow Conference T3 - Proceedings of the 31st Annual Western Snow Conference PB - Western Snow Conference CY - Yosemite National Park, California UR - sites/westernsnowconference.org/PDFs/1963Atwater.pdf ER - TY - Generic T1 - Aerial snow depth marker configuration and installation considerations T2 - 30th Annual Western Snow Conference Y1 - 1962 A1 - Miller, R.W. KW - Aerial markers, Equipment, Snow surveys AB -

A detailed description of aerial snow depth marker poles with cross-bars at 2 foot intervals, is shown in construction drawings and pictures. Site selection specifications are included in the text.

JF - 30th Annual Western Snow Conference T3 - Proceedings of the 30th Annual Western Snow Conference PB - Western Snow Conference CY - Cheyenne, Wyoming UR - sites/westernsnowconference.org/PDFs/1962MillerRW.pdf ER - TY - Generic T1 - Application of aerial snow cover observations to forecasting Flathead Lake inflows T2 - 30th Annual Western Snow Conference Y1 - 1962 A1 - Thoms, M.E. KW - Short term forecasting, Snow cover distribution, Water supply forecasting AB - A procedure is developed to forecast the potential inflow to Flathead Lake, on the Columbia River system in Montana by using the area covered by snow obtained by aerial flight and mapping during flight over the basin. The procedure is primarily for short term forecasting after May first. This information is used in reservoir regulation and management. The snow cover data is used in connection with temperature and current precipitation values. Reconstituted hydrographs are shown in comparison with observed hydrographs. JF - 30th Annual Western Snow Conference T3 - Proceedings of the 30th Annual Western Snow Conference PB - Western Snow Conference CY - Cheyenne, Wyoming UR - sites/westernsnowconference.org/PDFs/1962Thoms.pdf ER - TY - Generic T1 - Application of the electronic computer to seasonal streamflow forecasting T2 - 28th Annual Western Snow Conference Y1 - 1960 A1 - Codd, A.R. A1 - Farnes, P.E. KW - Electronic computer, Snow cover, Statistics, Water supply forecasting AB - A discussion pertaining to the use of the electronic computer for developing multiple regression formulas to be used in water supply forecasting for the rivers of Montana. The economics of using the electronic computers, to save man-hours, increase accuracy and have available a better selection of independent variables for use in the formula is brought out. Cost figures of manually operated calculators and the electronic computer handling the same, problem are shown.Discussion by Robert T. Davis indicates a confirmation of the economic value of using electronic computers for developing forecasting formulas. A step-by-step program for the computer is described and its benefits shown. JF - 28th Annual Western Snow Conference T3 - Proceedings of the 28th Annual Western Snow Conference PB - Western Snow Conference CY - Santa Fe, New Mexico UR - sites/westernsnowconference.org/PDFs/1960Codd.pdf ER - TY - Generic T1 - Automatic measurement of hydrologic paramaters at remote locations T2 - 28th Annual Western Snow Conference Y1 - 1960 A1 - Maxwell, L.M. A1 - Warnick, C.C. A1 - Beattie, L.A. A1 - Hespelt, G.G. KW - Telemetering systems AB - The purpose of a hydrologic telemetering system is to provide data on snowmelt runoff parameters from remote mountain locations at frequent intervals and at sites where such information is pertinent to operating reservoirs for flood control, irrigation, and power releases. The system is devised by the Engineering Experiment Station, University of Idaho at Moscow. The parameters selected for measurement are; total accumulation of precipitation, soil moisture, air temperature, snow quality (wetness), snow water equivalent, and the snow depth. A description and photos of the several procedures for measuring these parameters are shown, also schematic diagrams of the electronic telemetering systems at the sending and receiving end of the system. JF - 28th Annual Western Snow Conference T3 - Proceedings of the 28th Annual Western Snow Conference PB - Western Snow Conference CY - Santa Fe, New Mexico UR - sites/westernsnowconference.org/PDFs/1960Maxwell.pdf ER - TY - Generic T1 - The avalanche defence on the Trans-Canada highway at Rogers Pass T2 - 28th Annual Western Snow Conference Y1 - 1960 A1 - Schaerer, P.A. KW - Avalanche control AB - A detailed description of plans for highway maintenance through avalanche areas across Rogers Pass, British Columbia. Approximately 120 avalanche paths in 24 miles of highway are classified into four categories according to frequency of avalanche occurrence. A description of preventive or control measures for each category are suggested. Avalanche forecasting and warning procedures are explained together with plans for artificial release of small slides to prevent a disastrous avalanche. Maps and photographs depict the scope of the project.A formal discussion of the paper is presented by W.M. Borland, who cites technical problems of avalanche control on highways leading over the Rocky Mountains of Colorado. Avalanche control by artificial release are discussed. Comparisons of Colorado conditions are made with those conditions found on Rogers Pass. JF - 28th Annual Western Snow Conference T3 - Proceedings of the 28th Annual Western Snow Conference PB - Western Snow Conference CY - Santa Fe, New Mexico UR - sites/westernsnowconference.org/PDFs/1960Schaerer.pdf ER - TY - Generic T1 - Aerial reconnaissance of mountain snow fields for maintaining up-to-date forecasts of snow melt runoff during the melt season T2 - 27th Annual Western Snow Conference Y1 - 1959 A1 - Parsons, W.J. A1 - Castle, G.H. KW - Photography snow line, Runoff, Snow cover distribution, Snowmelt AB - A simple graphical method of determining the runoff volume to be expected after any date in the melt season by means of serial surveys of the snow line is described and evaluated on the basis of a 6-year study of the Kings and Kern River basins in California. Snow-line areas are sketched while in flight by using a transparent overlay on an aeronautical chart. Registration marks are placed on the overlay for use with subsequent flights. The areas are measured and the volumes computed. Water content of snow surveys are used to compute the volume of water remaining in the snowpack. This data is applied graphically to charts to determine the volume of water to be expected during the ensuing months of the runoff period. The resultant current forecasts had average errors of less than 10 percent during the critical period from 75-30 days before the end of the melt season. JF - 27th Annual Western Snow Conference T3 - Proceedings of the 27th Annual Western Snow Conference PB - Western Snow Conference CY - Reno, Nevada UR - sites/westernsnowconference.org/PDFs/1959Parsons.pdf ER - TY - Generic T1 - An approach to forecasting the spring runoff in Quebec T2 - 26th Annual Western Snow Conference Y1 - 1958 A1 - Cavadias, G.S. KW - Fkorecasting, Procedures AB - An approach to the problem of forecasting spring runoff is described with particular reference to the conditions in the Gouin Reservoir in Quebec which has a capacity of 6.5 million acre-feet and regulates the flow for the 7 hydro-electric plants on the St. Maurice River with a total installation exceeding 2.0 million H.P. The preliminary work that led to the selection of the variables is described, the individual variables are examined, and the frequency functions are discussed. The main advantages of the described method are that (1) the assumption regarding the total length of the flood period becomes unnecessary, and (2) a better understanding of the nature of the variables that influence the volume of the spring runoff is achieved. JF - 26th Annual Western Snow Conference T3 - Proceedings of the 26th Annual Western Snow Conference PB - Western Snow Conference CY - Bozeman, Montana UR - sites/westernsnowconference.org/PDFs/1958Cavadias.pdf ER - TY - Generic T1 - An application of snow survey data to glacier research T2 - 25th Annual Western Snow Conference Y1 - 1957 A1 - Meier, M.F. A1 - Simons, W.D. KW - Glacier research, Snow cover on glaciers AB - Snow surveys of a more complex procedure than usual are used in conducting research on glaciers to determine; (1) an understanding of the hydrology of glacier covered regions and (2), the use of glaciers as quantitative indicator of climate. Research project information gathered by the Geological Survey indicate the possibility of a backward look at climatic factors of past years. Data trends shown graphically for snow accumulation or ablation of the glaciers. Snow surveys on the glaciers at times use standard tubes but more often dig pits into the snow covering the glacier to ice, then use machine core drills for deep examination of the strata of the glacial ice. JF - 25th Annual Western Snow Conference T3 - Proceedings of the 25th Annual Western Snow Conference PB - Western Snow Conference CY - Santa Barbara, California UR - sites/westernsnowconference.org/PDFs/1957Meier.pdf ER - TY - Generic T1 - Aims and activities of the U.S. Advisory committee on weather control T2 - 22nd Annual Western Snow Conference Y1 - 1954 A1 - Orville, H.T. KW - Weather modification controls AB -

The duties and aims of the newly appointed Advisory Committee on Weather Control are explained in some detail. Reference is made to PROJECT CIRRUS, dealing with weather modification and the present state laws regulating weather modification in 7 western states and New York State. Reports of the committee will be unbiased and built on true facts of gathering and research project findings. In discussion Mr. Robert D. Elliott points out occurrences of possible bias in weather modification reports and expresses willingness to furnish information from western operators.

JF - 22nd Annual Western Snow Conference T3 - Proceedings of the 22nd Annual Western Snow Conference PB - Western Snow Conference CY - Salt Lake City, Utah UR - sites/westernsnowconference.org/PDFs/1954Orville.pdf ER - TY - Generic T1 - An approach to streamflow forecasting T2 - 21st Annual Western Snow Conference Y1 - 1953 A1 - Fulcher, M.K. KW - Statistical analysis, Water supply forecasting AB - A water supply forecast scheme is presented for the Colorado River above Grand Canyon. A statistical study of 9 tributary streams resulted in a decision to treat each tributary by itself and then route them by correlation procedures for a collective forecast at Grand Canyon. The Green River above Linwood is used as the pilot study. Data from 10 precipitation stations were weighed by the Thiessen method. These data were used as a soil priming factor from the preceding fall months. Snow survey data from 9 courses were used for April 1 forecasts. Fall and winter temperatures through March were used as a temperature factor. Multiple regression formula are solve with the 4 variables, resulting in a multiple correlation coefficient of 0.918. JF - 21st Annual Western Snow Conference T3 - Proceedings of the 21st Annual Western Snow Conference PB - Western Snow Conference CY - Boise, Idaho ER - TY - Generic T1 - Areal distribution of snow cover in relation to weather and terrain at Upper Columbia Snow Laboratory T2 - 16th Annual Western Snow Conference Y1 - 1948 A1 - Daniels, G.E. KW - Photographic analysis, Snow cover, Statistical analysis AB - A preliminary examination of the topographical features, vegetation cover, and snow cover of the Skyland Creek basin of the Upper Columbia Snow Laboratory was made by the use of vertical aerial photographs which were sampled by a series of points. These points were defined by a rectangular grid of 420 intersections within the basin. From the data thus obtained a statistical study of the effects of topography and vegetation on the snow cover and snow melting has been made.Discussion by Joseph B. Paulson. JF - 16th Annual Western Snow Conference T3 - Proceedings of the 16th Annual Western Snow Conference PB - Western Snow Conference CY - Reno, Nevada ER - TY - Generic T1 - Adjusting snow runoff correlation curves by use of autumn precipitation T2 - 16th Annual Western Snow Conference Y1 - 1948 A1 - MacLean, D.A. KW - Runoff, Snowmelt, Statistical analysis, Water supply forecasting AB - Stream runoff from snow is affected by the moisture content of the soil beneath the snow cover. Soil moisture condition is largely determined by precipitation during the autumn, months before the snowpack accumulates. Records of precipitation for August, September and October for 7 years at the Birchbank area of the Columbia River Basin were averaged and the departure from average was obtained for each year. Departure from average was multiplied by 1.5 and these corrections were added to or subtracted from the snow water content of the basin on each April 1. A graph of corrected snow water content against total streamflow showed closer correlation than when using uncorrected water content. Similar corrections for streamflow in other areas using factors of 0.5 and 3.0 show similar improvements in correlation. JF - 16th Annual Western Snow Conference T3 - Proceedings of the 16th Annual Western Snow Conference PB - Western Snow Conference CY - Reno, Nevada ER - TY - Generic T1 - The Army Weasel on Snow Survey Work T2 - 14th Annual Western Snow Conference Y1 - 1946 A1 - Allison, J.M. AB -

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JF - 14th Annual Western Snow Conference PB - Western Snow Conference CY - Sacramento, California UR - sites/westernsnowconference.org/PDFs/1946Allison.pdf ER - TY - Generic T1 - Additional arguments for modification of the national formula for runoff from small agricultural areas T2 - 12th Annual Western Interstate Snow Survey Conference Y1 - 1944 A1 - Snyder, C.G. KW - Flood hydrograph development, Hydrology, Small watersheds AB - The need for classification of the factors involved in the computation of runoff from small agricultural areas by using an expanded formula, is demonstrated. Factors are, precipitation intensity, soil condition, vegetative cover, infiltration rate together with time of occurrence and duration, with area involved, all must be used to clarify the simple formula without relying on a heavily weighted all covering constant. Tables and graphical examples are use to illustrate the development of flood hydrograph reproduction. The process is discussed by A. F. Pillsbury, J. B. Brown and R. W. Gerdel. JF - 12th Annual Western Interstate Snow Survey Conference T3 - Proceedings of the 12th Annual Western Interstate Snow Survey Conference PB - American Geophysical Union, Transactions, Part I: CY - Berkeley, California ER - TY - Generic T1 - Adjusting forecast curves for abnormal spring and summer temperatures T2 - 12th Annual Western Interstate Snow Survey Conference Y1 - 1944 A1 - Work, R.A. KW - Spring temperature modifications, Water supply forecasting AB - Factors affecting the snow and runoff relationship are listed, and a method presented for adjusting snow survey results of April 1 in constructing the forecast curve so as to compensate for temperature deviation from normal during the runoff season. The method is based on results of studies on two small drainage basins in Oregon. The selection of 2-month period of temperature departures as well as the correction coefficient to be applied are selected on the basis of the amount of water stored in the snow on April 1 as measured by snow survey . Results of the corrections as applied to both basins are tabulated and graphed for several years.Discussions are presented by Fred H. Paget, Harry Olsen, Ray K. Linsley, and Garfield Stubblefield. JF - 12th Annual Western Interstate Snow Survey Conference T3 - Proceedings of the 12th Annual Western Interstate Snow Survey Conference PB - American Geophysical Union, Transactions, Part I: CY - Berkeley, California ER - TY - Generic T1 - Analysis of high rages of snow melting T2 - 9th Annual Western Interstate Snow Survey Conference Y1 - 1941 A1 - Light, P. KW - Snow cover ablation, Snowmelt runoff AB - The heat exchange between warm, moist air and the underlying snow surface was found to be influenced chiefly by convection and condensation. These factors were expressed algebraically and combined to yield the effective snow melt. Logarithmic distributions of wind, temperature, and vapor pressure were assumed in developing this equation. Evaluation of constants involved in the turbulent transfer of heat required instruments at two levels in field observation but a single level may be used in connection with the equation for snow melt where reference levers are specified and the roughness parameter is known. The resulting equation then gives snow melt as a function of mean wind velocity, and vapor pressure. Application of this formula to a drainage basin necessitated evaluation of temperature and vapor pressure at different elevations by using conventional linear lapse rates. Corrections also are given for the modifications in the air mass as it moves over a large drainage area. The actual basin snow melt is taken proportional to the theoretical snow melt determined by the equation. The individual constant was evaluated by statistical methods. JF - 9th Annual Western Interstate Snow Survey Conference T3 - Proceedings of the 9th Annual Western Interstate Snow Survey Conference PB - American Geophysical Union, Transactions, Part I-B: CY - Sacramento, California ER - TY - Generic T1 - Analysis of snow cover and runoff in upper Snake, upper Yellowstone and Swift Current watersheds T2 - 7th Annual Western Interstate Snow Survey Conference Y1 - 1939 A1 - Monson, O.W. KW - Snow surveys, Soil moisture, Stastical methods, Water supply forecasting AB - Snow survey water content measurements are used as a basis for forecasting irrigation water supply, together with other factors closely allied with snow melt. Four factors are listed, (1) rainfall during the runoff period, (2) rainfall during the fall months before snow fall, contributing to soil priming and groundwater recharge, (3) deep percolation losses, (4) evaporation and transportation losses and sublimation of the snow pack. Measurable factors are by correlation coefficient values. A regression equation is developed and the least squares line is drawn through the plotted points on the graphs as a means of visual inspection. A discussion of the results of the study is included in the text of the paper. JF - 7th Annual Western Interstate Snow Survey Conference T3 - Proceedings of the 7th Annual Western Interstate Snow Survey Conference PB - American Geophysical Union, Transactions, Part I: CY - Spokane, Washington ER - TY - Generic T1 - Accuracy of Mount Rose spring balance T2 - 7th Annual Western Interstate Snow Survey Conference Y1 - 1939 A1 - Stevens, J.C. KW - Snow survey equipment, Weighing scales AB - A comparison was made of the relative accuracy of the Mt. Rose spring balance as improved by the Leupold, Vopel and Company of Portland, Oregon, and the Chatillon type with iso-elastic springs. The improved balance was within the limits of observational error of ordinary field work. It is believed that the accuracy of the simple springs can be further improved. The graduations were not tested for accuracy of machining. JF - 7th Annual Western Interstate Snow Survey Conference T3 - Proceedings of the 7th Annual Western Interstate Snow Survey Conference PB - American Geophysical Union, Transactions, Part I: CY - Spokane, Washington ER - TY - Generic T1 - Applying the Chatillon iso-elastic springs to the Mount Rose spring balance T2 - 6th Annual Western Interstate Snow Survey Conference Y1 - 1938 A1 - Elges, C. KW - Snow scales spring balance, Snow survey equipment AB - Temperature variations affecting the elasticity, creep and hysteresis of the metal of the springs and deviations from the shape in the stresses and transmitting machinery cause inaccuracies in spring scales. A new spring developed by J. Chatillon and Sons, made of an alloy called Iso-Elastic Metal eliminated the effects of temperature changes in the spring. The creep at stress of 60,000 lbs/sq in was reduced to less than 0.02% in deflection. The hysteresis was not over 0.02-0.04% of the full load deflection. A linear relationship of spring between load and deflection was obtained by using wire coiled with the axis of the wire parallel to the axis of the helix. Iso-Elastic springs were used in a Chatillon spring scale weighing 6 lbs, 5 oz. which gave an accuracy of 99.92%. A Mount Rose type of spring balance scale weighing 2 lbs. 12 oz. was constructed using Iso-Elastic springs. Further development of the scales is necessary to reduce it in size and weight before it can be used for snow surveys. JF - 6th Annual Western Interstate Snow Survey Conference T3 - Proceedings of the 6th Annual Western Interstate Snow Survey Conference PB - American Geophysical Union, Transactions, Part I: CY - Los Angeles, California ER - TY - Generic T1 - Anodyzing or hardening the surface of snow samplers T2 - 6th Annual Western Interstate Snow Survey Conference Y1 - 1938 A1 - Marr, J.C. KW - Snow samplers, anodyzing AB - Anodyzing duraluminum equipment hardens and smooths the surfaces, prevents oxidation and discoloration of hands and clothing, and increases the durability of the equipment. Anodyzing is recommended for snow samplers. The smoother surfaces permit the snow cores to slip through the tube easier, and less wear is exerted on the threads of the couplings. It is suggested that the cost of anodyzing may outweigh the advantages. JF - 6th Annual Western Interstate Snow Survey Conference T3 - Proceedings of the 6th Annual Western Interstate Snow Survey Conference PB - American Geophysical Union, Transactions, Part I: CY - Los Angeles, California ER - TY - Generic T1 - Accuracy of individual samples in a snow course T2 - 5th Annual Western Interstate Snow Survey Conference Y1 - 1937 A1 - Hunter, C.E. A1 - Devore, G.W. KW - Snow survey course analysis, Statistical methods AB - Variation in yearly water content of a particular sample point in relation to the water content average of the snow course was obtained for each of several years. Percentages of the mean of each sample for each year was then calculated. These data were tabulated and plotted under 'Scale' for water content and 'Percentage of Mean' for the percentage of the mean water content. The graph gave the relation of water content of each sample to the average of mean of the course for each year. When the percentage of the mean for any sample was widely scattered, the sample was considered unreliable. Unreliable areas were examined to locate the cause. It is believed that more research will result in establishing courses of 10 to 15 reliable sampling points. H.P Boardman presents a discussion of the paper and proposes methods of analysis and graphs for several snow survey courses and detailed reasoning in the text. JF - 5th Annual Western Interstate Snow Survey Conference T3 - Proceedings of the 5th Annual Western Interstate Snow Survey Conference PB - American Geophysical Union, Transactions, Part II: CY - Denver, Colorado ER - TY - Generic T1 - Application of snow survey data by the Bureau of Reclamation T2 - 5th Annual Western Interstate Snow Survey Conference Y1 - 1937 A1 - Reedy, O.C. KW - Reservoir regulation, Water supply forecasting AB - Snow survey data are used for forecasting water runoff on watersheds. The Bureau of Reclamation used the data from the Okanogan River Basin in Washington, The Malheur in Oregon, the Boise River Basin in Idaho, and the Jackson Lake and Snake River in Wyoming to forecast the water supply at Boulder Dam, Nevada. JF - 5th Annual Western Interstate Snow Survey Conference T3 - Proceedings of the 5th Annual Western Interstate Snow Survey Conference PB - American Geophysical Union, Transactions, Part II: CY - Denver, Colorado ER - TY - Generic T1 - Attachment of cutters and couplings; spanner wrenches T2 - 5th Annual Western Interstate Snow Survey Conference Y1 - 1937 A1 - Ryan, J.T. KW - Snow sampler coupling joints, Snow sampler cutter joints, Snow sampler test results AB - Experiments were conducted to develop a cutter joint between duraluminum tub and steel cutter to make a replacement of the cutter possible under field conditions. A threaded bushing provides a simple, positive, and reliable connection but usually requires a special wrench for removal. A soldered joint using aluminum solder produces greater strength and can easily be replaced by heat application. Soldering of couplings is recommended. Two models of a wrench designed to increase leverage and eliminate the probability of the pin being forced out of the hole were tested and found satisfactory. Their overall length is 8.5 in. and will not slip off the joint when in use. Information on aluminum solder and source of supply are included. JF - 5th Annual Western Interstate Snow Survey Conference T3 - Proceedings of the 5th Annual Western Interstate Snow Survey Conference PB - American Geophysical Union, Transactions, Part II: CY - Davis, California ER - TY - Generic T1 - The Adirondack snow surveys T2 - 4th Annual Western Interstate Snow Survey Conference Y1 - 1936 A1 - Cullings, E.C. KW - Snow survey equipment, Snow survey procedures AB - The topography and temperature of the 12,000 sq. mi. Adirondack Region in northern New York State is described. The drainage system consists of 12 streams flowing in all directions from the Central Highland. Systematical snow surveys were started about 1926 and are made on Feb. 1, Mar. 1, and about the third week in March of each year. Snow surveying equipment, consisting of snow tube, scale, hook, notebook, and canvas bag, is described in terms of construction and usage. Snow and water depths are tabulated and results plotted on a map at the conclusion of each survey. It is recommended that snow surveying be combined with ground water observations and that correlations between snow, ground water, and streamflow be studied. Instructions to observers on purpose, procedure, equipment, measurement and computation are presented. JF - 4th Annual Western Interstate Snow Survey Conference T3 - Proceedings of the 4th Annual Western Interstate Snow Survey Conference PB - American Geophysical Union, Transactions, Part II: CY - Pasadena, California ER -