TY - Generic T1 - Snowmelt Runoff in the Sierra Nevada and South Cascades during California’s 4th Year of Drought T2 - 84th Annual Western Snow Conference Y1 - 2016 A1 - Gary J. Freeman AB -

 For California statewide the 2015 water year, which followed three prior dry years, produced several new hydrometeorological records including but not limited to low runoff, dryness and warmer than normal minimum  temperatures.  The 2015 spring freshet from snowmelt reflected the general lack of snowpack, setting several new records for low spring flows leaving most of California reservoirs less than full.  Headwaters which drained the Sierra’s exposed granites suffered some of the lowest late summer and fall flows on record.  Northern California’s rivers such as the Pit, McCloud, Upper Sacramento, Klamath, and North Fork Feather River above Lake Almanor which have portions of their watersheds overlaying the High Cascades volcanic aquifer systems while at some of their lowest flow rates on record still managed to maintain higher flow rates than for the Sierra exposed granites. While water year precipitation was less than normal, the majority of precipitation occurred in December 2014 with storms delivering the majority of water year precipitation during a couple weeks mostly in the form of rainfall.  A large number of the storms that entered California during the 2015 water year occurred as atmospheric rivers with rainfall occurring on the higher headwater areas of the Sierra.  The relatively high elevation southern Sierra was much drier than northern California, so despite its higher elevation conducive to snowfall, precipitation was among the driest on record, leaving only a shallow snowpack on summits above 2,700-3,300 meters elevation.  Precipitation and unimpaired flows for the past four years were analyzed and compared with prior drought periods to gather perspective as to the severity of the drought.  Years such as the 2015 water year can provide foresight into what California’s late summer and fall mountain flows may look like with continued warming temperatures.  Several studies have indicated a significant reduction in snowpack for California’s mountain areas by the end of the 21st century.  (KEYWORDS: drought, climate change, snowpack, volcanic aquifer systems).

JF - 84th Annual Western Snow Conference CY - Seattle, Washington UR - /files/PDFs/2016Freeman.pdf ER - TY - Generic T1 - From Snow to Flow: Estimating the Timing of Peak Streamflow from SNOTEL Ablation Curves T2 - 83rd Annual Western Snow Conference Y1 - 2015 A1 - Kara J. Ferguson A1 - James McNamara A1 - Ron Abramovich A1 - Josh Johnston KW - melt-out timing KW - peak streamflow KW - probability KW - SNOTEL AB -

Predictions of peak streamflow timing in snow-dominated river systems are essential for proper water management and recreational availability. This study evaluates historic snow and streamflow data from 11 river basins throughout Idaho to investigate the relationship between snowmelt at SNOw TELemetry (SNOTEL) sites and peak streamflow within each basin. The goal is to provide a simple predictive tool that estimates the probability of peak streamflow occurring within a certain number of days as ablation progresses from 0 to 100%. For individual basins we evaluate melt-out levels in increments of 10% from each SNOTEL site and use a probabilistic modeling approach to develop cumulative distribution function (CDF) curves which illustrate the probability of peak streamflow occurring within a given number of days from the date at which the SNOTEL site reaches each melt-out level. Results from the CDF curves also provide anecdotal indices of peak streamflow timing.

JF - 83rd Annual Western Snow Conference T3 - Proceedings of the Western Snow Conference CY - Grass Valley, California UR - /files/PDFs/2015Ferguson.pdf ER - TY - Generic T1 - Planning Beyond California's Three-Year Drought - A 2015 Hydroelectric Planning Perspective T2 - 83rd Annual Western Snow Conference Y1 - 2015 A1 - Gary Freeman KW - climate change KW - drought KW - hydroelectric KW - reservoirs KW - Sierra AB -

Following three dry years, precipitation for the month of December 2014 was 131% of the Sierra Region’s 120-year December average; however October-December 2014 as a 3-month period continued to remain below average. On December 31, 2014, precipitation for the California Department of Water Resources (DWR) northern California 8-station index was 129% of its historical 30-year average. However DWR’s southern California 5- station index was only 70% of its 30-year historical average. Precipitation was much above average in northern Sierra and drier than average for the southern Sierra. In spite of this unbalanced situation statewide, the overall increase in precipitation appeared to many as a dramatic turnaround from one of the most severe droughts in California’s recorded history. However, in spite of this dramatic precipitation recovery, California’s snowpack at the end of December statewide was only 49% of average, thus remaining much below average, mostly due to the higher snowline accompanying the relatively warm December storms. For Pacific Gas & Electric Company which has historically produced about 38 percent of its conventional hydroelectric energy from the aquifer outflow of large volcanic springs in northern California and approximately 37% of its conventional hydroelectric energy from the snowpack, the fall rains after satisfying an unusually large soil moisture deficit made little difference in the outflow rates and added only meager amounts of recharge to northern California’s porous volcanic aquifer storage which had lost approximately four million acre feet from underground storage since 1999. The 2014 calendar year was highly unusual beyond its single characteristic of being dry. Minimum daily temperatures for the 12-month period for the Sierra Region were the warmest in 120 years of record. This additional heating resulted in some of the driest soils moisture conditions for California in the past 1200 years. While rain dominated precipitation caused flood damage in December for parts of California, river flows quickly declined following the December rains. Aquifer outflows in northern California continued to remain much below normal following December’s wetness. As of January 1, 2015, precipitation for the remainder of the water year would need to increase to about 135% of average to get 100% of average annual conventional hydro generation.

 

Presentation in PDF

JF - 83rd Annual Western Snow Conference T3 - Proceedings of the Western Snow Conference CY - Grass Valley, California UR - /files/PDFs/2015Freeman.pdf ER - TY - Generic T1 - The 2014 California Drought - Dealing with Extreme Dryness From A Hydroelectric Planning Perspective T2 - 82nd Annual Western Snow Conference Y1 - 2014 A1 - Gary J. Freeman KW - climate change KW - drought KW - hydroelectric KW - reservoirs KW - Sierra AB -

The 2013 calendar year was the driest year on record for California. For San Francisco based Pacific Gas and Electric Company (PG&E), which operates the largest investor owned hydroelectric system in the United States, the water management planning challenges, which were encountered during the first three months of 2014 and the twelve unusually dry months preceding 2014 were unlike those of earlier droughts. The acceptance of both the concept of climate change impacts as well as new paleo-climatological research findings about California and the southwest were for the first time being given serious consideration in the Company’s water release planning. The prospect that the persistent high pressure region blocking the storm track into California fromthe Eastern Pacific and Gulf of Alaska could possibly remain “parked in place” became a principal scenario needed for effective planning. In terms of snow water equivalent (SWE), the February 2014 statewide snow surveys were less than 15% of the historical February 1 average. The demands on downstream water release requirements for maintaining biological flows, whitewater rafting, and other recreational opportunities have continued to increase in the past 38- 39 years from the 1976-1977 drought, which were two successive very severe dry years. Conditions leading into the 2014 drought included 15-years of generally declining wetness over much of California causing the northern California’s porous volcanic aquifer storage to decline significantly from the aquifer’s relatively high mid-1990’s storage state. Also water year runoff from rain-shadowed areas of the northern California’s Sierra and southern Cascades have been in a state of trending decline since the 1976-1977 drought, a condition likely attributable to impacts from climate change. Utilizing the latest research findings available in 2014 on climate change and drought, the approach to reservoir and power production planning at PG&E changed from that utilized with prior droughts. Rather than assuming median likelihood or some low level of exceedances probability for remaining seasonal precipitation, the planning would take place as if the high pressure system pattern would continue to persist with no additional runoff expected.

JF - 82nd Annual Western Snow Conference T3 - Proceedings of the Western Snow Conference CY - Durango, Colorado UR - sites/westernsnowconference.org/PDFs/2014Freeman.pdf ER - TY - Generic T1 - Estimating Snow Water Equivalent at NWS Climatological Stations T2 - 81st Annual Western Snow Conference Y1 - 2013 A1 - Farnes, Phillip KW - density KW - precipitation KW - Snow water equivalent KW - snowmelt KW - temperature AB -

Typically, National Weather Service (NWS) Climatological Stations measure snow depth but not snow water equivalent (SWE). However, SWE is generally more important than depth when used in hydrologic and wildlife studies. Typically, there are higher elevation stations that measure SWE but lower elevations stations are predominately Climatological stations that do not measure SWE. New snowfall densities are generally between 6 and 10 percent while snow packs can reach densities into the 25 to 35 percent range just prior to and during melt. As part of developing the climatic database for the core area of the Greater Yellowstone Area (GYA), daily SWE was computed for all Climatological Stations. Some of these stations have snow courses at or near the station. Also, snow measurements were made at some of these stations in conjunction with the Snow Sinking Studies on the Northern Range of Yellowstone National Park. Methods for computing daily SWE using snow depth, precipitation and temperature will be presented as well as comparisons between estimated SWE and measured SWE at ten stations. The lengths of records where both measured and estimated SWE exist vary from about 17 years up to about 75 years. Long range trends of SWE will be shown for stations with longer records.

JF - 81st Annual Western Snow Conference T3 - Proceedings of the Western Snow Conference CY - Jackson Hole, Wyoming UR - sites/westernsnowconference.org/PDFs/2013Farnes.pdf ER - TY - Generic T1 - Modeling of Snowpack Accumulation and Losses in Mountainous Terrain for Both Snowpack Storage Mapping and Watershed Storage Estimates T2 - 81st Annual Western Snow Conference Y1 - 2013 A1 - Froyland, Hugo A1 - Stackhouse, Josh A1 - Schiefer, Erik A1 - Decker, Rand KW - ablation KW - accumulation KW - modeling KW - Snow water equivalent KW - snowpack KW - SWE KW - watershed AB -

A heuristic watershed-scale snowpack model that has been under development and verification at the University of Utah and now at Northern Arizona University since 1998 is now implemented on an articulate Geographic Information System (GIS) platform. Simple heuristic rules are established for the preferential accumulation and loss of snowpack in mountainous terrain. These rules include elevation and solar wattage, each at the pixel scale. The capacity for modern GIS to provide solar wattage explicitly from the root Digital Elevation Model (DEM), means that indexing this ablative potential with slope aspect and angle is no longer required. Each model run must be initialized with two snowpack Snow Water Equivalent (SWE) observations at different elevation within the watershed. One observation can be snowline. This means the model can be initialized for a water year start date, or an annual snowpack SWE maximum when it occurs, or forensic queries of historic events/years, and virtual events such as a “unit” storm or winter. Additionally, the efficiency with which a given watershed commutes water from snowpack storage to surface runoff is indexed with two different ratios; length of surface water channel in the watershed to area of the watershed, and length of watershed channel to watershed circumference. The test watersheds of Stackhouse (Rohde et al., 2012) are repeated with this model, and include four highland tributary watersheds in different physiographical provinces of the Rocky Mountains; Doyle Peak, San Francisco Peaks, Arizona; Kings Peak, Uintas, Utah; and Mt. Elbert and Jones Peak, Eastern San Juan Mountains, Colorado. These tributary sub-basins ranged in size from 88 to 210 million square meters. Snowpack accumulation and/or loss is modeled to the DEM pixel scale, in all of these cases, 30m by 30m. Snowpack SWE in storage, per pixel, is then integrated for an estimate of watershed aggregate snowpack SWE storage. As an aid in identifying watersheds that are particularly effective at snowpack SWE storage, this model allows for the comparison of SWE volumes in a given watershed to the area of the watershed; a measure of the watershed’s snow water volume to area efficiency. Another valuable data product of the model is a detailed mapping of snowpack SWE storage within the watershed at the pixel scale. This information can be used in a variety of ways. As examples of the decision support capabilities of the model, three water resource decision space challenges are investigated in an effort to demonstrate the utility of the model and include the following:

JF - 81st Annual Western Snow Conference T3 - Proceedings of the Western Snow Conference CY - Jackson Hole, Wyoming UR - sites/westernsnowconference.org/PDFs/2013Froyland.pdf ER - TY - Generic T1 - Value Added Products T2 - 80th Annual Western Snow Conference Y1 - 2012 A1 - Farnes, Phillip E. JF - 80th Annual Western Snow Conference PB - Western Snow Conference CY - Anchorage, Alaska UR - sites/westernsnowconference.org/PDFs/2012Farnes.pdf ER - TY - Generic T1 - Gauge Conversion Effects on Long-Term Precipitation Comparison and Records T2 - 80th Annual Western Snow Conference Y1 - 2012 A1 - Fisher, Daniel B. KW - long-term precipitation records KW - precipitation gauge KW - SNOTEL AB -

Climate sites measure precipitation using a variety of methods and sensors. Each individual sensor has its own catch efficiency which varies with solid and liquid precipitation. A climate site’s precipitation record may contain data from two or more types of precipitation gauges. Using parallel data from the accumulation gauges at four SNOTEL sites in Alaska, comparisons were made of the effects gauge transitions have had on the long term record. The records of each site indicate that significant change in gauge catch can occur with gauge transitions, though the variations cannot be tied to gauge type alone. These transitions should be taken into consideration when developing long-term assessments and while comparing recent data with earlier years. (KEYWORDS: precipitation gauge, SNOTEL, long-term precipitation records)

JF - 80th Annual Western Snow Conference T3 - Proceedings of the Western Snow Conference PB - Omnipress CY - Anchorage, Alaska UR - sites/westernsnowconference.org/PDFs/2012Fisher.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 - Montana Electronic Precipitation Map T2 - 79th Annual Western Snow Conference Y1 - 2011 A1 - Farnes, P.E. A1 - Huddleston, J. A1 - Flynn, K. KW - Montana, annual precipitation, Kriging, climatological stations, isohyetal, multivariate interpolation, annual precipitation AB - An accurate estimate of average annual precipitation (AAP) is a necessity for completing hydrologic analysis, developing stream flow statistics, or doing other related water resource planning. Tools to develop and complete such analysis are required, capable of very quickly updating AAP information as it become available, and available for widespread use without proprietary requirements. To meet such a mandate, we developed a free-ware UNIX based tool called PMAP, which allows rapid AAP estimates through universal Kriging. A case study was implemented for the state of Montana using the 1981-2010 water-year averages and a 400 m elevation grid. While there are many geo-statistical techniques to choose from in completing such analysis, the strength in our work is not necessarily the method that we selected, but rather the data supporting it. We compiled AAP estimates for over 1,400 stations across the region including 1,100 stations in Montana, and 300 adjacent to the state. We evaluated the data using a number of geostatistical analysis techniques. Isohyetal lines were set at 50 mm (2 inch) increments under 500 mm (20 inches) and 250 mm (10 inch) increments above 500 mm (20 inches). The1981-2010 AAP map (isohyets and grids) will be available through the Montana Natural Resource Information System (NRIS) web site electronically, and software will be made available from the Montana Department of Environmental Quality upon request 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/2011Farnes.pdf ER - TY - Generic T1 - Climate Change and the Changing Water Balance for California's North Fork Feather River T2 - 79th Annual Western Snow Conference Y1 - 2011 A1 - Freeman, G.J. KW - Precipitation, climate change, Feather River, orographic, water balance, rain shadow, northern California AB - Climate change has likely had a large role the changing water balance on northern California's North Fork Feather River (NFFR) in recent years. In addition to changes in both snowpack quantity and timing of the spring snowmelt, some of its subbasins are also revealing a declining trend in water year runoff, while others do not. NFFR's complex terrain geometry includes a combination of both windward facing slopes and rain-shadowed leeward slopes that result in a mix of climatic gradients. The combined effect of having relatively low elevation and topographic barriers in the form of mountain ridges provide opportunity for both orographic cooling to take place on the windward slopes and compressional warming to take place on the leeward slopes as the airflow of frontal systems pass through the NFFR Basin. On the leeward, rain-shadowed slopes, air descends and warms quickly through compressional heating. Precipitation amounts quickly diminish as the descending air warms and increases its capacity to hold moisture. Both the Lake Almanor and East Branch of the North Fork Feather (EBNFFR) subbasins are two rain-shadowed subbasins that exhibit a declining trend in water year runoff. Trend declines that approach 308 hm3 (250,000 AF)/year collectively from the two subbasins since the early 1960's were analyzed using a water balance approach to help understand the declining runoff trend in terms of changes taking place at the watershed level. The decrease in both the low elevation snowpack and the water year runoff has resulted in a decline in hydroelectric output and less outflow of the NFFR into Lake Oroville. 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/2011Freeman.pdf ER - TY - Generic T1 - An Experimental and Modeling Investigation of the Impact of Silvicultural Manipulation on Snow Hydrology in the Cedar River Watershed, WA T2 - 78th Annual Western Snow Conference Y1 - 2010 A1 - Forsyth, J. A1 - Lundquist, J. A1 - Wayand, N. KW - Snow water equivalent, seasonal runoff, runoff timing, timber harvest effects, Cedar River AB - Over the past 80 years, forest harvesting throughout the western U.S. has resulted in a shift in the dominant forest structure to young, dense forests. Meanwhile, declining trends in mountain snow water equivalent (SWE), summer river flow, and earlier snowmelt have largely been attributed to climate with little consideration of the impact of the concurrent changes in vegetation from forestry practices. Silvicultural manipulation has the potential to increase snow water storage, change snowmelt timing and restore ecological processes that might normally be adversely affected by climate change. This study is primarily concerned with snowmelt timing, since it is crucial to watershed management in basins with limited reservoir storage. Any delay in snowmelt from silvicultural manipulation could reduce winter flood hazards and increase summer runoff when water demand for cities and agriculture is the highest. This study commenced in the 2009 water year and takes place in the Cedar River Watershed, WA, located in the climate-sensitive intermittent snow zone. Using a combination of distributed field measurements and point and distributed hydrologic models, we are investigating i) the heterogeneity of snow accumulation and melt in different forest structures, and ii) which forest changes are of comparable magnitude to climate change in their effects on snow hydrology. JF - 78th Annual Western Snow Conference T3 - Proceedings of the 78th Annual Western Snow Conference PB - Western Snow Conference CY - Logan, UT UR - sites/westernsnowconference.org/PDFs/2010Forsyth.pdf ER - TY - Generic T1 - Tracking the Impact of Climate Change on Central and Northern California's Spring Snowmelt Subbasin Runoff T2 - 78th Annual Western Snow Conference Y1 - 2010 A1 - Freeman, G.J. KW - PG&E, California, subbasin runoff, snowmelt, climate change, topographic control AB - A simplified index system was set up at Pacific Gas & Electric Company (PG&E) to evaluate the current impact of climate change and produce a simplified trend forecast of spring snowmelt runoff for relatively small hydroelectric operational subbasins in central and northern California. The need for PG&E to classify and index these relatively small subbasin drainages in terms of runoff impact from climate change became apparent with the need to increase overall awareness of the relatively rapid change in water availability timing since about 1970 and to focus on identifying potential associated business risks. Spring runoff from snowmelt has historically been depended upon for filling the nearly one hundred seasonal reservoirs that PG&E manages. Within any given large watershed, there are considerable differences in the characteristics of contributing subbasin reaches, and those characteristics influence how the subbasin runoff will respond to climate change. Isohyetal maps can sometimes be utilized to identify these areas from averaged precipitation amounts that are often related to topography and elevation differences. During this review, it was found that orographically influenced subbasins were least impacted from the effects of climate change, while those areas that were either in a rain shadow or were behind topographic barriers revealed larger climate change impact in the form of reduced snowpack, spring runoff, and sometimes runoff for the water year. JF - 78th Annual Western Snow Conference T3 - Proceedings of the 78th Annual Western Snow Conference PB - Western Snow Conference CY - Logan, UT UR - sites/westernsnowconference.org/PDFs/2010Freeman.pdf ER - TY - Generic T1 - Diminishing Snowfall in Central and Northern California's Mixed Rain and Snow Elevation Zone T2 - 77th Annual Western Snow Conference Y1 - 2009 A1 - Freeman, G.J. KW - Declining snowfall, California mountains, mid-elevation zone, cooperator stations AB - Snowfall over large areas of the low elevation snow zone in central and northern California below the 1,524 m (5,000 ft) elevation has significantly diminished since the mid-twentieth century and for some areas where it has historically snowed, precipitation now occurs only as rainfall. An analysis of snowfall measurements from several NOAA National Weather Service cooperative weather stations throughout central and northern California revealed a significant decrease in measured snowfall in recent years. Earlier studies have mostly focused on snow courses and automated snow sensors at elevations above 1,524 m (5,000 ft). This study analyzed snowfall measurements only between the 457 m (1,500 ft) and 1,524 m (5,000 ft) elevations. Snowfall is typically measured manually utilizing a snowboard that is measured daily, swept clean, and then reset for the following day's collection. Some of the NOAA cooperator climate stations offer usable data and are an excellent source for evaluating low elevation precipitation type utilizing measured snowfall. Several mountain communities in California exist in the rain-snow zone between the 457 m (1,500 ft) and 1,524 m (5,000 ft) elevations. Continuing reductions in snowfall for these mountain communities reduces the need for snow removal equipment, designing building structures for heavy snow loads, and is creating a changed winter lifestyle, one with less snowfall. 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/2009Freeman.pdf ER - TY - Generic T1 - Snow Sinking Studies T2 - 76th Annual Western Snow Conference Y1 - 2008 A1 - Farnes, P.E. KW - Predator-prey, snow condition, foot pressure, snow density AB - In snow covered regions, predator-prey relationships change with snow conditions. Some snow conditions are advantageous to the predators while other snow conditions favor the prey species. To understand the relationship between bearing pressure imposed by the various animals and how deep they sink into the snowpack, and different snow parameters, 193 measurements were taken over a 13 year period. Most of the sampling was done in Yellowstone National Park on the Northern range at four to six locations three to four times each winter. Curves were developed to predict how far an animal or object having a known bearing pressure will sink into a snowpack of a given depth and density. Equipment developed and procedures used will be described. Results have been combined into a graph to simplify use. Data is particularly important to evaluating animal's ability to move through snow and predator-prey relationships involving snow, but can also be used to evaluate how deep oversnow vehicles, helicopters with snow pads, skis or snow shoes sink into the snowpack. 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/2008Farnes.pdf ER - TY - Generic T1 - Climate Change and Flood Control Operations in the Sacramento Basin T2 - 76th Annual Western Snow Conference Y1 - 2008 A1 - Fissekis, A. A1 - Lund, J. A1 - Townsley, S. A1 - Brekke, L. A1 - Fickensher, P. A1 - Faber, B. KW - Climate change, flood control, rule curves, runoff timing, CNRFC AB - Shasta, Oroville and New Bullards Bar reservoirs are being studied to determine how Northern California's flood control projects respond to climate changed inflows. The goal of this project is to identify why flood control curves should be based on data-gathering and technological improvements that have occurred since the curves were created in the mid-1900s. In collaboration with the Institute for Water Resources, the Bureau of Reclamation, the California-Nevada River Forecast Center (CNRFC) and the Hydrologic Engineering Center, the U.S. Army Corps of Engineers is using climate projections for the year 2030 to test how flood control rule curves respond to changes in timing and magnitude. Preliminary research indicates that both temperature and precipitation changes will occur during that period and that they will alter historically observed flows. As California receives most precipitation between November and May, adapting to changes in peak flow timing and snowmelt runoff is not only crucial to reserve an adequate supply of water into the summer and fall, but also to ensure adequate flood storage. 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/2008Fissekis.pdf ER - TY - Generic T1 - Runoff Impacts of Climate Change on Northern California's Watersheds as Influenced by Geology and Elevation - A Mountain Hydroelectric System Perspective T2 - 76th Annual Western Snow Conference Y1 - 2008 A1 - Freeman, G.J. KW - Sierran watersheds, basalt rock, spring flow, Pit River, Yuba River, runoff timing, runoff quantity AB - Northern California's Pit, McCloud, Feather, Yuba, and American Rivers each have regional differences that set them apart from the higher elevation, less porous Sierra watersheds to the south. The watersheds from Lake Almanor north are primarily characterized by relatively porous volcanic basalt rock flows with several large springs that provide a large sustained base flow component. Relatively low overall elevation sets these northern watersheds apart as some of the first watersheds in California anticipated to be affected from climate-induced change to snowpack. During an average water year, for much of the Pit and McCloud Rivers, approximately 80-90 percent of river runoff is water from past years that emerge from springs as aquifer outflow. For those rivers that overlay large volcanic aquifers, the form of precipitation has much less significance on runoff timing than watersheds south of Lake Almanor. Climate change is not anticipated to significantly affect timing and quantity of runoff for the basalts, but it will likely have relatively large timing and quantity changes for the Yuba, American, and some reaches of the North Fork Feather River. The Yuba River Basin which has a relatively large proportion of exposed granite in its headwaters is revealing a significant timing shift in runoff into earlier months. This will have effects on hydrogeneration and reservoir operation. 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/2008Freeman.pdf ER - TY - Generic T1 - Estimating Average Annual Runoff from Montana Streams T2 - 75th Annual Western Snow Conference Y1 - 2007 A1 - Farnes, P.E. KW - Runoff prediction, Montana, SNOTEL, precipitation, cover type, fire history AB - Procedures for estimating runoff from un-gaged streams will be presented. First and most important is to have an accurate average annual precipitation map for the current base period. The precipitation map needs to be based on a maximum elevation grid of 500 meters and preferably a 100 to 200 meter grid. It needs to be based on a procedure that looks at the nearest two or three neighbors and one that assigns measured values to measured points. The Montana SILC3 Land Cover Classification provides the cover types for most areas. Some of the 36 different cover types that have similar hydrologic responses can be combined for hydrologic analysis. Data from SNOTEL sites and climatological stations in the area was used to determine the relationship between average annual precipitation, average April 1 snow water equivalent, and average April through July precipitation for the current base period. Average annual precipitation and runoff from gaged streams in the area and percent forested area for each gaged watershed are used to determine a runoff vs. precipitation curve for drainages if all of the forest was removed. By applying factors from the cover type vs. forest species age curves, the runoff was determined for the area of each cover type in each precipitation zone. These were accumulated to determine runoff for each watershed or HUC of interest. Using fire history or logging by decades, usually available from land managing agencies, it was possible to determine changes in runoff by decade from any given watershed. 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/2007Farnes.pdf ER - TY - Generic T1 - Precipitation Phase Discrimination by Dew Point and Air Temperature T2 - 75th Annual Western Snow Conference Y1 - 2007 A1 - Feiccabrino, J. A1 - Lundberg, A. KW - Precipitation phase, air temperature, Sweden, tree canopy AB - Correctly reported precipitation phases are crucial for estimation of snow storage in hydrological, regional and global climate models. Precipitation phase is especially critical for models simulating processes in tree canopies, since the canopy storage capacity is about one order of magnitude larger for snow than rain. The number of manned meteorological stations is decreasing, making determination of precipitation phase more difficult. Most hydrological models use an air temperature threshold to separate rain from snow, but there are indications that a dew-point temperature threshold might work better. This study utilized forty-five years of three-hour man-made observations for nineteen Swedish station ranging from 55 deg N to 68 deg N consisting of precipitation mass and phase, air and dew point temperatures. Precipitation events were classed as snow or rain, excluding mixed precipitation, were used for the initial analysis. Air temperature was found to be a better indicator of precipitation phase then dew point temperature. On occasion 0 deg C is used as an air temperature threshold, but if the air temperature rain/snow threshold 0 deg C is replaced by 1.0 deg C, the misclassified precipitation would be reduced by almost half in Sweden. 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/2007Feiccabrino.pdf ER - TY - Generic T1 - Seasonal Snow Extent and Snow Mass in South America Using SSM/I Passive Microwave Data (1988-2003) T2 - 75th Annual Western Snow Conference Y1 - 2007 A1 - Foster, J.L. A1 - Hall, D.K. A1 - Chiu, L. A1 - Kelly, R./Powell, H. KW - Seasonal snow cover, SSM/I, South America, satellite AB - Seasonal snow cover in extra-tropical areas of South America was examined in this study using passive microwave satellite data from the Special Sensor Microwave Imagers (SSM/I) on board the Defense Meteorological Satellite Program (DMSP) satellites. For the period from 1988-2003, both snow cover extent and snow mass were estimated for the months of July, typically the coldest winter month. Most of the seasonal snow in South America is in the Patagonia region of Argentina. The average snow cover and snow mass for the 16-year period was 284,492 km2 and 0.763 x 1013 kg, respectively. The year with the greatest average snow extent and snow mass during the 16-year period of record was 1992 -- 551,875 km2 and 2.073 x 1013, respectively. If the strong El-Nino years of 1991-1992 and 1997-1998 are excluded, the July snow mass shows a linear trend of 28% over the 16 years period, with a p-value of 0.0098, which is significant at the 85% level. 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/2007Foster.pdf ER - TY - Generic T1 - A Cloudseeding Program to Increase Aquifer Outflow in Northern California's McCloud and Pit River Watersheds T2 - 75th Annual Western Snow Conference Y1 - 2007 A1 - Freeman, G.J. KW - Pit River, McCloud River, cloudseeding, hydrogeneration, snowpack, PG&E AB - Northern California's Pit and McCloud River watersheds overlay a combination of highly fractured porous, volcanic High Cascade and flood basalts. Pacific Gas and Electric Company (PG&E) is completing a project that will place 15 ground based cloud seeders in the mountains on and around Mt. Shasta. These seeders will be remotely operated and disperse heated plumes of silver iodide crystals to enhance snowfall over several hundred square miles of forested watershed. A natural lag in runoff response is expected to provide increased outflow from the springs, even during dry years when there may be a scarcity of clouds to seed. Adding additional snow to the snowpack utilizing cloudseeding is anticipated to enhance aquifer pressure increasing naturally occurring groundwater outflow from springs by as much as 9%. The increased artesian outflow is anticipated to increase the McCloud and Pit River combined runoff by 308 cubic hectometers (250,000 acre feet) or by approximately 0.35% producing approximately 330 gigawatt hours per year (GWh/year) additional hydroelectric generation. The increased runoff delivered daily throughout the year from springs can provide additional opportunity for downstream residential, agricultural, and industrial use as it passes through Shasta Lake, the Sacramento River, and eventually entering the San Francisco Bay estuary. 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/2007Freeman.pdf ER - TY - Generic T1 - Change in the Date of Snow Disappearance in the High Arctic T2 - 74th Annual Western Snow Conference Y1 - 2006 A1 - Foster, J.L. A1 - Robinson, D.A. A1 - Hall, D.K. A1 - Estilow, T. KW - Arctic snow cover, satellite, snowline retreat, climate change AB - In this paper, we show changes in the dates of snow disappearance in the high Arctic (70° north latitude) between the late 1960s and the early 2000s. NOAA satellite data were employed to make these snow observations (from snow cover to snow free conditions), using arbitrary but consistent boundaries. Continuing the study presented by Foster et al, (1992) on springtime snow disappearance in the high Arctic, the date the snowline retreats during the spring (when it first moves north of the 70 degree parallel), for many Arctic locations, has occurred approximately a week earlier in recent years compared to the late 1960s. The tendency toward earlier snowmelt previously observed during the past several decades has apparently neither been a local phenomenon nor a short-term fluctuation. However, unlike other markers of climate warming in the Arctic, since 1990, the date of snow disappearance has not occurred noticeably earlier. It is possible that the date of snow disappearance is not an adequate benchmark for detecting warming signal. 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/2006Foster.pdf ER - TY - Generic T1 - Climate change in Montana T2 - 73rd Annual Western Snow Conference Y1 - 2005 A1 - Farnes, P.E. KW - Climate change, Montana, snow courses, Glacier National Park, temperature increases, tree canopy AB - Records from climatological stations having approximately 100 years of record and snow courses with approximately 75 years of record were analyzed to determine how temperatures, precipitation, and snowpack have changed over the past 100 years. There were 24 snow courses in Montana with about 70 years of record that were analyzed. Trend analysis indicates an average of about 15 percent decrease in April 1 snow water equivalent. However, three snow courses in Glacier National Park that have been measured for over 80 years show an upward trend of about 4 percent over the 70 year period and a 13 percent increase for the 83 year record. Part of the explanation of decreasing snow packs might be related to increasing tree canopy cover. Those that are located in more open areas show less of a decrease than those located in more timbered stands. Trend analysis for these 17 stations showed the average annual temperature has increased about 1.40 C over the past 100 years. None of the stations show any acceleration of temperature increases in the more recent years suggesting that increases may be more natural than man caused. The trend of annual precipitation at 20 stations (four in Northwest Wyoming) showed an increase of about two percent over the last 100 years. However, some stations showed increases while others showed decreases. Again, there does not appear to be different rates of change in recent years compared to earlier years. 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/2005Farnes.pdf ER - TY - Generic T1 - Contributions of Snow Research to Forest Watershed Management in the Southwestern United States T2 - 71st Annual Western Snow Conference Y1 - 2003 A1 - Ffolliott, P.F. A1 - Gottfried, G.J. KW - Snowpack, research, southwest US, watershed management AB - Snowpacks that accumulate on high-elevation forested watersheds are an important source of water in much of the southwestern United States. However, snowpacks in this region differ from those in more northern regions because of the variability in annual snowfall accumulations and the intermittent melting throughout the winter season. Snow research over the past 50 years has indicated that there are possibilities of increasing snowmelt-runoff through the implementation of forest management practices. The effects of these forest management practices can often be predicted from inventory-prediction relationships. Other research has resulted in development of snow-runoff forecasting procedures and simulation models of forest snowpack dynamics leading to increased knowledge of snow hydrology. 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/2003Ffolliott.pdf ER - TY - Generic T1 - Climate Change and California's Diminishing Low-Elevation Snowpack - A Hydroelectric Scheduling Perspective T2 - 71st Annual Western Snow Conference Y1 - 2003 A1 - Freeman, G.J. KW - Climate change, Feather River, hydrogeneration, runoff timing, decreased snowpack, reservoir carryover AB - Pacific Gas and Electric Company's (PG&E) Water Management Team did a review to identify possible effects on PG&E's hydro generation production of an increase in winter runoff from rainfall and a decrease in spring runoff from snowmelt. There are many indications that the reduced snowpack in the low-elevation Sierra snow zone, which has been observed in recent years, is a likely consequence of climate change. Climate change appears to be affecting runoff timing and flow quantities most significantly for those relatively low-elevation watersheds, which are situated from the Yuba River north. For PG&E, both the Feather River and the Yuba River Basins have large portions of their drainages at relatively low elevation and appear most sensitive in terms of potential to affect future hydro generation schedules. The November-through-February winter runoff quantities, which are mostly rainfall-produced, appear to have increased both in intensity and monthly quantity; and the spring snowmelt in the low elevations, from a somewhat diminished snowpack, appears to be taking place almost a month early for some portions of the Feather River. Full reservoirs near the end of the snowmelt period are a desirable outcome for meeting critical summer and fall electric load demands. 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/2003Freeman.pdf ER - TY - Generic T1 - SNOWPACK MODELLING OF THE SALT BASIN WITH WATER MANAGEMENT IMPLICATIONS T2 - 69th Annual Western Snow Conference Y1 - 2001 A1 - Fassnacht, S.R. A1 - Helfrich, S.R. A1 - Lampkin, D.J. A1 - Dressier, K.A. A1 - Bales, R.C. A1 - Halper, E.B. A1 - Reigle, D. A1 - Inman, B. KW - Colorado River, SCA, AVHRR, Snowpack estimates AB -

The NOAA/NWS National Operational Hydrologic Remote Sensing Center produces maps of the areal extent of snow-cover over the Western US to assess the state of the snowpack. The binary product represents snow-no snow, but cannot estimate the snow-covered extent within an individual pixel (1 kin2). For the Colorado River Basin, fractional snow-covered area (SCA) has been derived from Advanced Very High Resolution Radiometer (AVHRR) data by the NASA Southwest Regional Earth Science Applications Center. The SCA maps are combined with snow water equivalent maps to develop snowpack water volume estimates. The uncertainty of using the binary product instead of the fractional SCA product for total SCA and snowpack water volume estimates were compared for the Salt-Verde watershed in central Arizona. The basin volume estimates derived from a combined binary SCA product and SWE estimates were evaluated assuming uniform 1%, 50%, 100% SCA and a linear and quadratic relationship between SCA and elevation. Inherent errors in the AVHRR fractional SCA and SWE product propagate into the snowpack water volume estimates. Snowpack estimates derived from AVHRR sub-pixel products are more accurate than the binary estimates.

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/2001Fassnacht.pdf ER - TY - Generic T1 - Equivalent permeability of a continental, alpine snowpack T2 - 67th Annual Western Snow Conference Y1 - 1999 A1 - Fox, A.M. A1 - Williams, M.W. KW - Lysimeters, Meltwater flow, Snowpack permeability AB - Most snowpacks are not homogeneous, but consist of a number of snow and ice layers with varying permeabilities. In such cases, an 'equivalent' permeability can be used as an integrated or bulk property of the entire snowpack depth and is a useful parameter for gravity-flow and numerical models of meltwater flow through isothermal snowpacks. Calculated surface meltwater flux and Iysimeter discharge were used to establish daily relationships between specific meltwater fluxes and wavespeeds through the snowpack at a continental, alpine site in 1996 and 1997. These relationships were used to determine a pore-size distribution index (E) and to calculate equivalent permeability. Values for E were found to vary considerably and could not be related to other measured snowpack properties. Values were in the lower range of those previously reported, often less than 3, and were highly dependent on the range of meltwater fluxes used in calculations. Equivalent permeability was also at the lower limit of values reported in the literature, and varied by 2 orders of magnitude from 1.08 x 10 to the 11th to 2.79 x 10 to the 8th m2. In 1997 it declined considerably over 16 days. JF - 67th Annual Western Snow Conference T3 - Proceedings of the 67th Annual Western Snow Conference PB - Western Snow Conference CY - South Lake Tahoe, California UR - sites/westernsnowconference.org/PDFs/1999Fox.pdf ER - TY - Generic T1 - Runoff forecast error uncertainty and some ways it can affect snowmelt water scheduling decisions in the Sierra T2 - 67th Annual Western Snow Conference Y1 - 1999 A1 - Freeman, G.J. KW - Forecasting, Optimization, Reservoir operation, Snowmelt AB - Forecasting runoff and scheduling reservoir releases for PG&E's hydroelectric system, located in California's Sierra and Southern Cascade Watersheds, requires that watersheds be subdivided into subbasin reaches between diversion dams to facilitate computation of daily unimpaired sidewater inflow for each subbasin reach. Computation of daily unimpaired subbasin sidewater flow allows hydro schedulers to construct a feasible operation plan that optimizes water releases from upstream reservoirs for purpose of maximizing hydroelectric value while satisfying multiple constraints such as are often imposed for instream flows, whitewater rafting, planned maintenance, and recreation. What occurs with subbasin daily flow computation is large variance among successive daily flows. This variance is seldom explainable by hydrologic events alone. However an explanation can be found, when one reviews propagation of error uncertainty and daily storage change taking place at upstream reservoirs. In addition the April through July seasonal runoff forecast has a tendency to carry the full standard error of the estimate forward into the final ablation phases of snowmelt. At that point, the relative magnitude of the error compared with remaining flow yet to come causes large error uncertainty that often affects optimal final seasonal filling of reservoirs. JF - 67th Annual Western Snow Conference T3 - Proceedings of the 67th Annual Western Snow Conference PB - Western Snow Conference CY - South Lake Tahoe, California UR - sites/westernsnowconference.org/PDFs/1999Freeman.pdf ER - TY - Generic T1 - Stepwise multiple regression snow models: GIS applications in the Marmot Creek basin, (Kananaskis Country, Alberta) Canada and the National Park Berchtesgaden, (Bayern) Germany T2 - 65th Annual Western Snow Conference Y1 - 1997 A1 - Forsythe, K.K. KW - GIS, Landsat, Modeling, Principal component analysis, Thematic Mapper AB - Geographic Information Systems (GIS) and satellite remote sensing are now used extensively in analyses of natural environments. This research examined the usefulness of a GIS and remote sensing based approach for integrating many different and widely varying data sources. The multisource data sets were used in stepwise, multiple linear regression models that analyzed the variation in snow dept and snow-water equivalent (SWE) depth.Models were developed in the Marmot Creek Basin using landsat Thematic Mapper (TM) satellite data, Digital Elevation Model (DEM) data and various mapped data layers in combination with historical snow depth and SWE measurements. The best model for snow depth produced a coefficient of determination or adjusted R2 of 0.6370. The independent variables of elevation, incidence, tree height and principal component four of the TM data could explain approximately 64% of the variation in snow depth. The best model for SWE depth had an adjusted R2 of 0.5814. The independent variables that explained the variation in SWE depth were elevation, incidence, and TM band seven. The National Park Berchtesgaden models build upon the approach used in the Marmot Creek Basin. landsat TM data and a DEM provided the basis for the regression independent variables. Additional analyses of these data were performed within the GIS to calculate variables such as across and down slope curvature and a Normalized Difference Vegetation Index (NDVI). The best model for snow depth produced an adjusted R2 of 0.801 while the SWE result was 0.843. The variables providing the explanation in snow depth variation were elevation and NDVI. SWE depth variation was explained by elevation, across slope curvature, TM band seven and principal component four of the TM data. 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/1997Forsythe.pdf ER - TY - Generic T1 - 'Hydro-fuels-', Maintenance-, and Pricing Risk Management -Changing Times in Snow Zone Water Management T2 - 65th Annual Western Snow Conference Y1 - 1997 A1 - Gary J Freeman KW - Pacific Gas & Electric, AB 1890, ISO, Deregulation AB -

In August 1996, the California Legislature passed legislation (AB 1890) that established new policies and restructured California's electric Industry. The Bill established an Independent System Operator (ISO), a Power Exchange (PX), a rate-reduction financing program, a public benefits program, and called for increased system reliability. With the deregulation of California's electric utility industry taking place, the water management team at Pacific Gas and Electric Company (PG&E), an investor owned utility, is facing a new challenge. Future pricing uncertainty will likely become as important to snow zone reservoir management as seasonal remaining weather uncertainty has traditionally been for forecasting snowmelt runoff and maximizing hydro generation in the past. While PG&E has been utilizing probabilistic extended streamflow predictions for some time in making hydroelectric scheduling decisions, it has only recently begun to look at how weather uncertainty will be handled by energy traders that are selling electricity into the California Power Exchange and eventually into a futures market. Electricity futures market pricing (one to three months ahead) is beginning to have a significant effect on how much risk an operator may be willing to take with regard to storing water in anticipation of a better price at some future date. In a sense, water is perishable with regard to use for hydro generation. If stored, there is risk that the weather could turn wet and that water may be spilled past fully loaded powerhouses

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/1997Freeman.pdf ER - TY - Generic T1 - Estimating monthly distribution of average annual precipitation in mountainout areas of Montana T2 - 63rd Annual Western Snow Conference Y1 - 1995 A1 - Farnes, P.E. KW - GIS, Lapse rate, Models, Precipitation distribution AB - Many computerized models and Geographic Information Systems (GIS) are being used to estimate average annual precipitation in mountains of the western United States. In most areas, there is a good correlation between average annual precipitation and elevation and most models use elevation to distribute annual precipitation to unmeasured areas. There is an increasing need to distribute these annual values to monthly averages. Some models use elevation to distribute monthly precipitation. Some models use the monthly distribution for long-term valley stations to distribute annual precipitation in higher elevations. Studies in Montana show there is a significantly different distribution of monthly precipitation between valley and mountain areas, particularly in the winter and spring months. Comparisons for some watersheds in Montana are shown and proposed procedure for distributing annual precipitation into realistic monthly increments is presented. JF - 63rd Annual Western Snow Conference T3 - Proceedings of the 63rd Annual Western Snow Conference PB - Western Snow Conference CY - Sparks, Nevada UR - sites/westernsnowconference.org/PDFs/1995Farnes.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 - Estimating localized SWE on the Yellowstone northern range T2 - 61st Annual Western Snow Conference Y1 - 1993 A1 - Farnes, P.E. A1 - Romme, W.H. KW - Algorithm, SNOTEL, Snow cover AB - After the large fires of 1988 in Yellowstone National Park, many projects were initiated to study their effects. One of the studies involved the effects of fire on vegetation and ungulates on the northern winter range.Because snow water equivalent (SWE) is a significant factor in animal foraging and movement, it was necessary to develop a method that could use data from National Weather Service (NWS) climatological stations and Soil Conservation Service (SCS) snow courses and SNOTEL (SNOw Survey TELemetry) sites to predict SWE in areas of varying slopes, aspect, elevation, and forest cover. It was first necessary to estimate SWE at NWS climatic stations. The daily snow depth, precipitation and temperature values were used to estimate daily SWE. Daily SNOTEL SWE was used to estimate daily SWE at SCS snow courses. Algorithms were developed to estimate daily SWE for flat and open areas on the northern range not having significant drifting similar to data collection sites.A multidimensional nomograph was developed from measured data to estimate SWE for any slope and aspect within the northern range area. The habitat cover type was used to adjust SWE for forested areas.Techniques and relationships developed for the northern range would be transferable to other intermountain areas that accumulate a winter snowpack and that have daily climatic and/or snow pillow data. 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/1993Farnes.pdf ER - TY - Generic T1 - North American snow cover variability from satellite data (1972-1993) and comparison with model output T2 - 61st Annual Western Snow Conference Y1 - 1993 A1 - Frei, A. A1 - Robinson, D.A. KW - Climate change, Model, Snow cover AB - A twenty-one year record of remotely-sensed areal snow cover fluctuations for the Northern Hemisphere is examined, with particular emphasis placed on North America. No trend is apparent, but several periods of positive and negative departures are found. The mid- to late-1970s, and the mid 1980s, had large snow covered areas. The early 1980s, and the period since 1987, are characterized by low snow cover. The most temporally extensive of these has been a period of snow deficit since 1987, particularly in spring and in eastern North America. The five lowest North American spring snow covers on record have occurred since 1987. In autumn, three of the last five years have been extremely low. Recent winters have not been anomalous. Results from one climate model are compared to observations, and are found to simulate accurately winter snow cover on the continental scale, while slightly under-estimating spring and autumn values. On the regional scale, the model is less accurate. Snow cover may be critical for model validation, improvement of parameterizations, and for prediction and detection of climate change. 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/1993Frei.pdf ER - TY - Generic T1 - Simulation of snowmelt in a small rangeland watershed T2 - 60th Annual Western Snow Conference Y1 - 1992 A1 - Flerchinger, G.N. A1 - Cooley, K.R. KW - Energy balance, Hydrologic modeling, Snowmelt modeling AB - Snowmelt simulation of the Simultaneous Heat And Water (SHAW) model was tested by applying the model to two years of data from three sites on a rangeland watershed ranging from transient snow cover on a west-facing slope. The SHAW model is a point energy and mass balance model and simulates a one-dimensional profile extending from the snow, residue or soil surface to a specified depth within the soil. The model’s ability to simulate heat and water movement through plant cover, snow, residue and soil has been demonstrated, but the accuracy of the model in predicting snowmelt outflow has never been tested. The timing and magnitude of simulated hourly and daily snowmelt compared well with measured values. Results suggest that the SHAW model can be applied successfully to predict snowmelt from diverse rangeland sites. 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/1992Flerchinger.pdf ER - TY - Generic T1 - A scaled index of winter severity T2 - 59th Annual Western Snow Conference Y1 - 1991 A1 - Farnes, P.E. KW - Precipitation, Snow, Temperature, Wildlife, Winter severity, Yellowstone National Park AB - A procedure for indexing the severity of a winter would be helpful to wildlife managers and general public in understanding how mild or how severe conditions are for any given season or month. The Scaled Index of Winter Severity (SIWS), has a scale from -4.0 for most severe to +4.0 for mildest with 0 being near a normal winter. The index uses minimum daily temperatures, snow depth, snow water equivalent, snow density and precipitation accumulation (or SWE), above or below a threshold level. The weightings and threshold for each parameter can be changed to represent different species. Stations can be accumulated or weighted to represent winter range areas. Months can be looked at individually or accumulated for a season. Depending on the area, summer growth on winter ranges may also be a factor affecting winter severity.Frequency analysis of data provides probability of nonexceedance that is used to determine the level of any given component or combined components for the winter severity index.Trends of SIWS for a portion of Yellowstone National Park for the past 40 years is presented. 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/1991Farnes.pdf ER - TY - Generic T1 - Changes in the timing and magnitude of high and low flows, 1958-1988, Eagle Creek, Oregon T2 - 58th Annual Western Snow Conference Y1 - 1990 A1 - Fedora, M.A. KW - Oregon, Regression, Snowmelt AB - Eagle Creek is located on the south face of the Wallowa Mountains in northeastern Oregon and has a snow dominated runoff regime. A multiple regression approach was used to detect changes in streamflow extremes over a 31 year period. Measures of snow-water equivalent, temperature, precipitation and time were used as independent variables with peak flows and the timing and volume of streamflow available for irrigation as dependent variables. The magnitude of peak flows was best explained by the April 1 snow-water equivalent. Variation in the timing of low flows during the irrigation season was best explained by the April 1 snow-water equivalent and mean April-June temperature. The volume of streamflow through the irrigation season (July 1-September 30) was best explained by the April 1 snow-water equivalent, mean April-June temperature and time (in years). The time variable was significant at the 90% confidence level and indicated that streamflow available for irrigation increased by an average of 0.038 inches per year (316 acre-feet per year) over the study period. JF - 58th Annual Western Snow Conference T3 - Proceedings of the 58th Annual Western Snow Conference PB - Western Snow Conference CY - Sacramento, California UR - sites/westernsnowconference.org/PDFs/1990Fedora.pdf ER - TY - Generic T1 - Learning from watching snowmelt T2 - 58th Annual Western Snow Conference Y1 - 1990 A1 - Frazier, J.W. A1 - Brandow, C.A. KW - Bed load movement, Ice flow, Oversnow flow, Rain-on-snow, Snowmelt observations, Stream morphology, Subalpine meadows AB - The WRENSS handbook contains a hydrologic procedure for estimating increased water yield from silvicultural treatments. The difference in annual evapotranspiration for a forested watershed under harvested and unharvested conditions approximates the annual water yield increase. Annual water yield inreases predicted by WRENSS require area precipitation and general forest stand characteristics. However, forest stand characteristics had little effect on predicted water yields. Annual water yield estimates were only as accurate as the basin wide precipitation data. The WRENSS predicted water yield increases were accurate for the snow dominated region. Potential model upgrades include improved estimates of snow vaporization, evapotranspiration rates, indexed precipitation or orographic functions, and assessment of streamfow generation processes from alpine areas for water yield increases in alpine-subalpine basins. JF - 58th Annual Western Snow Conference T3 - Proceedings of the 58th Annual Western Snow Conference PB - Western Snow Conference CY - Sacramento, California UR - sites/westernsnowconference.org/PDFs/1990Frazier.pdf ER - TY - Generic T1 - Estimating the effects of wildfires on water supply in the northern Rocky Mountains T2 - 57th Annual Western Snow Conference Y1 - 1989 A1 - Farnes, P.E. A1 - Hartman, R.K. KW - Water supply forecasting, Wildfire AB - Wildfires during the summer of 1988 burned a significant portion of several Northern Rocky Mountain wastersheds. A procedure was needed to adjust pre-burn calibrated water supply forecasting procedures to reflect post-burn conditions. The described procedure operates with a set of physically based, empirical relationships derived from data collected in Western Montana and Northwestern Wyoming. The premise of the procedure is that a reduction in timber canopy will lead to reduced interception of snowfall and spring precipitation. It is proposed that reduce summer evapotranspiration will have a minor effect on the concurrent seasonal volume. Instead, reduced summer evapotranspiration will have its greatest effect on the following season's volume by providing a higher level of antecedent soil moisture. 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/1989Farnes.pdf ER - TY - Generic T1 - pH of mountain snowfall in Montana 1981-1984 T2 - 53rd Annual Western Snow Conference Y1 - 1985 A1 - Farnes, P.E. KW - Acid rain, Acid snow, pH AB - For the past four winters, the pH of surface snow has been measured at many snow courses in western Montana in conjunction with regularly scheduled snow surveys. This paper describes the field procedures used to obtain pH values and it summarizes year to year variation in pH and the possible sources for the acidic snow. 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/1985Farnes.pdf ER - TY - Generic T1 - A comparison of melt rate methods used in forecasting runoff from an Alberta mountain environment T2 - 53rd Annual Western Snow Conference Y1 - 1985 A1 - Ferner, S. A1 - Wigham, J. KW - Melt rate, Snow pillow, Snowmelt, SSARR AB - A split watershed version of the Streamflow Synthesis and Reservoir Regulation (SSARR) model was calibrated and verified for a small forested research watershed located in the Rocky Mountains west of Calgary. Five different techniques used to estimate melt rate were applied to the model to determine which provides the best forecasting result. The melt rate in mm/degree day C was the only input parameter changed in the model, which was run for the months of April, May and June over an eight year period, 1973-1980. Model performance was best using melt rates calculated from snow pillow data. An average melt rate from the snow covered area, as determined by five snow pillows at sites of different elevation and exposure provided the best forecasting result. Measured melt rates from just one snow pillow located at the middle elevation of the basin (2155 m) in a heavily forested area provide a comparable result. Snow pillows located at lower elevations in either open or closed areas, and snow pillows located at higher elevations in open areas provide a poor result. 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/1985Ferner.pdf ER - TY - Generic T1 - Does Your Snow Sampler Overmeasure? T2 - 52nd Annual Western Snow Conference Y1 - 1984 A1 - Farnes, Phillip E. A1 - Richards, R.P. AB -

If you are using the Standard Federal or Mt. Rose snow tubes and weighing scales to measure snow water equivalent, you are not alone. A large volume of snow data is still obtained by this method, and will continue well into the foreseeable future. As more people begin to rely on automatic sensors for their snow data, it is important to realize that such sensors do not measure the same as the manual core sampler. This discrepancy was the subject of several years of research that went into the Western Snow Conference's Report on Metrication of Manual Snow Sampling Equipment.

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/1984FarnesB.pdf ER - TY - Generic T1 - Predicting time of peak snowmelt runoff from snow pillow data T2 - 52nd Annual Western Snow Conference Y1 - 1984 A1 - Farnes, P.E. KW - Peak flow, Snow pillows, Snowmelt AB -

The first snow pillow was installed in Montana in 1963. Since then nearly 70 remote snow sensors have been installed and automated. These snow sensors accurately assess the effect of warming spring temperatures by measuring the daily snow water equivalent of the mountain snowpack. Simple time-sequence relationships between snowmelt and day of peak streamflow add another dimension to the hydrologist's ability to predict significant hydrologic events. To determine a relationship requires a few years of snow pillow records and streamgage data. To project dates of peak streamflow requires frequent measurements of snowmelt progress, usually from a real-time data collection system such as SNOTEL. This method provides a simple, realistic estimate of peak flow dates on streams where daily runoff forecast models have not yet been developed, where existing models cannot accurately predict date of peak flow, or as a check for peak flow dates projected with existing models.

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/1984FarnesA.pdf ER - TY - Generic T1 - Rain-on-snow flood event in central Arizona T2 - 51st Annual Western Snow Conference Y1 - 1983 A1 - Ffolliott, P.F. A1 - Brooks, K.N. KW - Arizona, Flooding, Rain-on-snow, Streamflow forecasting AB - To better understand the effects of rain-on-snow precipitation events and to improve streamflow forecasting, events surrounding a flood which occurred on the Salt-Verde River Basins (Arizona) in February 1980 were examined. Precipitation, temperature, lysimeter runoff, and streamflow data from the upper and lower elevational zones were analyzed. A description of the study site and the type of precipitation (rain, snow, or mixed rain and snow) which the various elevations received are given. Also, a sequence of events can be seen by the comparison of precipitation, temperature, lysimeter runoff, and streamflow, which are graphically illustrated. It was concluded that, although snowmelt augmented streamflow, rainfall was the primary cause of the flood. 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/1983Ffolliott.pdf ER - TY - Generic T1 - Metrication of manual snow sampling equipment by western snow conference metrication committee T2 - 50th Annual Western Snow Conference Y1 - 1982 A1 - Farnes, P.E. A1 - Peterson, N.R. A1 - Goodison, B.E. A1 - Richards, R.P. KW - Equipment - snow surveying, Equipment - Testing, Metrication, Snow sampler, Snow surveys AB - After four years of field testing, the Western Snow Conference Metrication Committee is presenting its proposal and design of two metric snow samplers.The WSC snow sampler for the deeper western snowpacks has 10.6 cm sq cutter area while the ESC-30 sampler for shallow snowpacks (up to 1 m depth) has 30 cm sq cutter area.The proposal is based on extensive field tests to compare ground truth with the standard Federal Snow Sampler, the proposed metric snow samplers, and other snow samplers. The committee developed drawings and specifications for the new metric snow samplers. The commmittee also proposes a method for converting the present standard Federal sampler into a metric sampler. JF - 50th Annual Western Snow Conference T3 - Proceedings of the 50th Annual Western Snow Conference PB - Western Snow Conference CY - Reno, Nevada UR - sites/westernsnowconference.org/PDFs/1982Farnes.pdf ER - TY - Generic T1 - Northern hemisphere snow cover conditions during the winter of 1982 T2 - 50th Annual Western Snow Conference Y1 - 1982 A1 - Foster, J. A1 - Ormsby, J. A1 - Rango, A. KW - Eurasia, North America, Satellite, Snow cover AB - During the winter of 1982 (December - February) the mean snow covered area in North America was the third greatest in the 16 year record (1966 - 1982). In Eurasia the snow covered area was near normal. But the snow covered area in both North America and Eurasia increased significantly over that of the previous year. Assessment of any long term climatic trends must wait extension of the snow cover data base. JF - 50th Annual Western Snow Conference T3 - Proceedings of the 50th Annual Western Snow Conference PB - Western Snow Conference CY - Reno, Nevada UR - sites/westernsnowconference.org/PDFs/1982Foster.pdf ER - TY - Generic T1 - Proposed metric snow samplers T2 - 48th Annual Western Snow Conference Y1 - 1980 A1 - Farnes, P.E. A1 - Goodison, B.E. A1 - Peterson, N.R. A1 - Richards, R.P. KW - Equipment, Metrication, Snow sampling, Snow Water Equivalent AB - In June 1978 the Western Snow Conference selected a committee to develop a plan and criteria for unified development and testing of metric snow samplers. The proposed design of metric snow samplers is presented. Field meaasurements made both with existing and proposed snow sampling equipment are tabulated. Comparisons between different cutters and the accuracy of each based on 1978-79 data are presented. Criteria for the proposed metric snow samplers and procedures that can be used to modify present equipment are discussed. 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/1980Farnes.pdf ER - TY - Generic T1 - Mapping snow surface temperature from thermal satellite data in the southern Sierra Nevada T2 - 48th Annual Western Snow Conference Y1 - 1980 A1 - Frampton, M. A1 - Marks, D. KW - Remote sensing, Snow hydrology AB - Mapping snow surface temperature over a large alpine area is a useful tool for monitoring the surface evergy exchange. In this study, Tiros-M satellite data are used to measure snow surface temperatures over very complex terrain in the southern Sierra Nevada. The satellite data are compared to extensive field measurements collected at the time of satellite overpasses. The reliability of the data is very good in areas of total snowcover (0.99 degrees K), but is degraded in areas of mixed trees or rocks, and snow. Because the satellite data were received in Field Station Format, accurate geometric rectification and subsequent registration to terrain coordinates was not possible. An approximate registration allowed the satellite determined surface temperatures to be used to compute incoming longwave and net radiation over the Glen Pass area in the southern Sierra Nevada. This is done to illustrate that satellite derived surface temperatures can provide useful information on the energy exchange over snow in an alpine environment which may lead to improved snowmelt runoff prediction. 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/1980Frampton.pdf ER - TY - Generic T1 - Future operations with SNOTEL T2 - 46th Annual Western Snow Conference Y1 - 1978 A1 - Farnes, P.E. KW - Hydrologic data, Telemetry AB - The implementation of the SNOTEL (Snow Survey Telemetry) by Soil Conservation Service will cause many changes in the methods, training, and analysis of current snow survey techniques. Real time data will provide significant input to streamflow models, filling the historic void of good data from the main water producing zone. Calibration of ungaged or gaged watersheds for inputing extreme storm events will provide improved design data for reservoirs and land use planning. Accuracy of short range streamflow forecasts will be improved. The frequency of manual snow surveys at most unautomated sites can be reduced to once or twice a year. The date of manual snow surveys will become less critical. Estimates of water equivalent at manual snow courses can be made for the first of each month based on real time data from SNOTEL sites and correlation methods. Manual surveys at automated sites can be limited to times when a site is visited for maintenance after an initial calibration period between snow pillow and snow course has been established. Field snow surveyors will become fewer in number, more mobile and better trained. Reports will be more aligned with changes in water supply conditions than calendar dates. 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/1978Farnes.pdf ER - TY - Generic T1 - Developing techniques for measuring precipitation T2 - 46th Annual Western Snow Conference Y1 - 1978 A1 - Foehner, O.H. KW - Precipitation gages AB - Although precipitation has been measured for thousands of years, its reliability has been frequently (and justifiably) questioned. Within Project Skywater, a variety of field programs from California to Kansas underwrite instrument development and testing to improve reliablility and accuracy of data collection over wide areas at reasonable cost. Skywater data collection systems range from fence post gages to satellites. Instruments such as auto siphons and digitally recording radar have been tested with varying degrees of success. When measuring snowfall, comparisons indicated that both the snow pillow and the heated tipping bucket gage tended to undermeasure, while standard weighing bucket gages are subject to bridging and in heavy snowfall areas do not have adequate capacity. Although large orifice, high capacity weighing bucket gages hold promise of avoiding these problems, additional field tests are needed. Data relay alternatives have also been investigated. The Landsat satellite has been tested and compared with more conventional telemetry. The limited periods of response available from orbiting satellites has led to a current test with GOES for more frequent interrogations. 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/1978Foehner.pdf ER - TY - Generic T1 - The Southwest's frozen assets: snowpack management T2 - 45th Annual Western Snow Conference Y1 - 1977 A1 - Ffolliott, P.F. A1 - Thorud, D.B. KW - Snowpack management, Watershed management AB - In the arid Southwest, less than 20% of the average annual precipitation is recovered for use by man. However, water yield improvement experiments have demonstrated the feasibility of increasing runoff from snow accumulations on forested watersheds through various management practices. Based upon the hypothesis that greater accumulations of snow contribute to increased runoff, the effects of reducing forest densities and removing forest overstories upon the amount of snow trapped and subsequently recovered in the form of snowmelt runoff--have been assessed. In addition, studies have been designed to examine the behavior of intercepted snow, while, theoretical studies, which supplement other investigations, have been undertaken. Hopefully, these research efforts will provide guidelines for forest management to enhance snowmelt water yield and, at the same time, be compatible with wood, forage, and wildlife production, and recreational use of forest lands. 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/1977Ffolliott.pdf ER - TY - Generic T1 - Weather modification - a major resource tool T2 - 45th Annual Western Snow Conference Y1 - 1977 A1 - Foehner, O.H. KW - Economic aspects of weather modificatio, Weather modification AB - Weather modification has been identified as a significant source of new water in several major planning documents including the 'Westwide Study' and 'The Report on Water for Energy in the Upper Colorado River Basin.' Project Skywater's results support these conclusions. There is increasing evidence that the potential for increasing the water supply of the Western United States through snow augmentation is very good. Recent evaluation of winter experiments provides new support for the estimated potential increase in snowfall with cloud seeding. A study is now underway to identify seedability criteria and increase efficiency through better control of seeding operations. Both additional research and new operational application of the existing technology are progressing in a number of locations including California, Utah, and Colorado.The impact on energy production, irrigation, water quality, municipal and industrial use, and recreation is significant. 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/1977Foehner.pdf ER - TY - Generic T1 - Impacts of energy development on the waters of the northern Great Plains T2 - 45th Annual Western Snow Conference Y1 - 1977 A1 - Fogarty, W.J. KW - Water consumption for energy, Water management AB - Development of the energy resources, particularly coal, is now and will continue playing an ever increasing role in the future of the West. The main questions are where, when and to what extent will the development occur. One of the main restricting factors in answering these questions is the availability of water. In the Upper Missouri Basin estimates are that agriculture accounts for over 90% of the present consumptive water use, urban growth approximately 4% and mining far less than 1%. Projecting to the year 2000 when coal production could reach 400 million tons annually, water consuption due to mining is predicted at 7-14,000 acre feet, which represents only about 1/10th of the current water consumption for the region. Energy conversion facilities principally gasification and electric generating plants, are being projected to use approximately 77% of the total annual consumptive use in the Northern Great Plains region by 2000. In 1970, the average annual streamflows in the Upper Missouri Basin amounted to approximately 26 million acre feet. 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/1977Fogarty.pdf ER - TY - Generic T1 - Public response to proposed snowpack augmentation in the Sierra Nevada T2 - 43rd Annual Western Snow Conference Y1 - 1975 A1 - Farhar, B.C. A1 - Mewes, J. KW - Weather mods - sociological effects AB - During the summer of 1974, a series of 21 public meetings was held in the northern Sierra Nevada about a proposed orographic cloud seeding pilot project sponsored jointly by the State of California and the USBR. The purposes of the meetings were to inform the public and to activate citizen participation early in the planning process.Comments and questions arising from the meetings are summarized and analyzed from a sociological perspective. Comments are categorized by topical area (including general information, project justification, potential benefits, and potential problem areas); the highest proportion of comments are with regard to potential problems connected with the project. The major problem areas addressed by citizens were extra-area effects, flooding, environmetntal/ecological concerns, and local damage and costs. Comments are stratified by geographical location of the meeting site (mountain, valley, or lee, in relation to the contemplated project target area). Differences in the kinds of comments are found by location. 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/1975Farhar.pdf ER - TY - Generic T1 - Snow maps for the Canadian Hydrological Atlas T2 - 43rd Annual Western Snow Conference Y1 - 1975 A1 - Findlay, B.F. KW - Mapping - hydrological data AB - The Hydrological Atlas of Canada which will be published in 1976 will contain more than 40 pages of full-colour plates. Maps will be in scales of 1:10,000,000 and 1:20,000,000.The five maps and texts which the author is directly involved with are treated briefly. These five are: (a) annual precipitation, (b) annual snowfall, (c) snow cover formation and loss, (d) maximum depth and time of snow cover, (e) snow cover networks. 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/1975Findlay.pdf ER - TY - Generic T1 - Thermal conductivity - basis of a potential method for determining in situ snow density T2 - 42nd Annual Western Snow Conference Y1 - 1974 A1 - Fowler, W.B. KW - Snow - density - measurement AB - An instrument for rapid determination of thermal conductivity of liquids and solids is described. From the known relationship between thermal conductivity and snow density, measurements can be calibrated in terms of snow density. With a small, 4-mm-diameter probe of coaxial design and differential temperature measurements, rapid, single value reasings are made in a few seconds. These readings compare favorably with the customary thermal conductivity analysis in which a time-temperature relationship developed over many minutes is normally required. Equipment is small, lightweight. and portable.A calibration of the density probe in liquids and snow (density range of 0.06 to 0.4) is shown. JF - 42nd Annual Western Snow Conference T3 - Proceedings of the 42nd Annual Western Snow Conference PB - Western Snow Conference CY - Anchorage, Alaska UR - sites/westernsnowconference.org/PDFs/1974Fowler.pdf ER - TY - Generic T1 - Mountain precipitation and hydrology for snow surveys T2 - 39th Annual Western Snow Conference Y1 - 1971 A1 - Farnes, P.E. KW - Forest canopy, Forest cover, Precipitation analysis, Snow water equivalent AB - On snow course locations in timbered areas the amount of snow that occurs in open meadow situations is determined by adjusting snow course readings proportionately to the forest canopy cover at the sampling points. This open meadow or natural snowfall value for average April 1 snow water equivalent is compared to average annual precipitation at locations where both values are available. From this relationship, average annual precipitation is determined for all snow course sites. Using precipitation data and elevation, isohyets are drawn. The hydrology of various drainages is evaluated by determining the relationships between precipitation and runoff is obtained by determining the average annual precipitation for gaged drainage basins and comparing this to average runoff. By uning these relationships the average runoff for any basin can be estimated by using average annual precipitation over the basin. 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/1971Farnes.pdf ER - TY - Generic T1 - Efficiency of foliage in horizontal interception T2 - 39th Annual Western Snow Conference Y1 - 1971 A1 - Fowler, W.B. A1 - Berndt, H.W. KW - Condensation, Hoar frost, Rime ice AB - Comparing deposition of rime and condensation growth of hoarfrost on a number of simple geometric solids and complex foliar elements indicates major differences occur in these processes with time. Differences in the rate of rime accumulations are a reflection of the changing effective surface accompanying simplification of form and enlargement of receptor elements. Heat loss through forced convection appears to be a major factor in condensation growth of hoarfrost. 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/1971Fowler.pdf ER - TY - Generic T1 - Snow and reservoir management for the Columbia River treaty decision T2 - 38th Annual Western Snow Conference Y1 - 1970 A1 - Fisher, W.H. A1 - Sporns, U. KW - Flood control, Power generation, Reservoir regulation, Water supply forecasting AB - Management of Columbia River Treaty storage reservoirs in Canada to increase hydroelectric power generation and flood control in the United States and Canada is described. Water management criteria are presented, consisting of operating rules, seasonal runoff forecasting procedures and short-term streamflow forecasting methods. The criteria, primarily derived by empirical methods, attempt to optimize the storage operation. Draft of the storage is governed by power generation requirements and seasonal runoff forecasts; refill of the storage is governed by seasonal runoff forecasts, short-term forecasts and power generation requirements.The seasonal runoff forecasts consider combined winter precipitation and snowpack water equivalent, spring and summer precipitation, antecedent precipitation and mean monthly maximum temperatures of the forecast period. Glacier melt is considered in the Mica drainage basin. 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/1970Fisher.pdf ER - TY - Generic T1 - The relationship of snowpack density and water content changes of runoff on a small watershed in Arizona T2 - 37th Annual Western Snow Conference Y1 - 1969 A1 - Ffolliott, P.F. A1 - Thorud, D.B. KW - Ablation, Snowmelt research, Snowpack density AB - A research project is discussed dealing with snow density and the development of an index to snow ‘ripening’ during the snowmelt season producing varying quantities of runoff. The object of this study was to obtain basic inventory data on the spatial and temporal variations in snowpack density and associated water content, and to relate these variations to hydrograph characteristics. Also, an attempt is made to determine how peak snowpack density and water content are affected by differences in timber stocking, elevation and insolation. The study was carried out on a 425-acre ponderosa pine watershed located in north-central Arizona. Snow samples were taken at 195 sampling points located in a grid fashion over the basin. Sets of samples were taken at regular intervals during the melt season. 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/1969Ffolliiott.pdf ER - TY - Generic T1 - Criteria for determining mountain snow pillow sites T2 - 35th Annual Western Snow Conference Y1 - 1967 A1 - Farnes, P.E. KW - Snow pillow, Snow pillow location AB - Snow pillows and radio telemetry sites in remote mountainous areas are more costly to locate than regular snow courses. Considerably more time and effort is necessary for selection of good data collection sites which will provide a sound basis for streamflow forecasting. Criteria for site selection are outlined and multiple regression analysis provided for snow courses on five Montana streams. Findings for determining good snow course locations are cited. 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/1967Farnes.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 - Soil Moisture Measurement in Water Supply Forecasting T2 - 34th Annual Western Snow Conference Y1 - 1966 A1 - Fletcher, J.E. KW - Soil moisture, Soil moisture instruments, Water supply forecasting - soil moisture AB -

The several known instruments and procedures for measuring the moisture in the soil under a blanket of snow are taken up in detail with discussion. Neutron scattering; resistance method with porous blocks; capacitance method; Colman blocks; fiberglass and monel metal with temperature cell; thermal radiation units; gravity sample method; air humidity; heat conductivity; tensiometers. The procedure in which this soil priming factor is used in water supply forecasting is explained, as one of the important variables for the regression or correction to snow survey or precipitation data.

JF - 34th Annual Western Snow Conference T3 - Proceedings of the 34th Annual Western Snow Conference PB - Western Snow Conference CY - Seattle, Washington UR - sites/westernsnowconference.org/PDFs/1966Fletcher.pdf ER - TY - Generic T1 - Fisheries management of Yellowstone Lake, Wyoming, as related to water supply forecasting T2 - 32nd Annual Western Snow Conference Y1 - 1964 A1 - Farnes, P.E. A1 - Bulkley, R.V. KW - Fisheries management, Water supply forecasting AB - A unique application of water supply forecasting is developed for predicting the rise of Yellowstone Lake in Yellowstone National Park, as effecting the growth or decline in the production of cutthroat trout. The need for such foreknowledge is shown in a discussion of fisheries management procedures. The forecasting procedure was first derived graphically and later refined by electronic computer, multiple correlation procedures to use 4 independent variables, height and date of peak rise in the lake are forecast accurately. In discussion Mr. C. H. Clay covers other factors effecting fisheries management and stream control. JF - 32nd Annual Western Snow Conference T3 - Proceedings of the 32nd Annual Western Snow Conference PB - Western Snow Conference CY - Nelson, British Columbia UR - sites/westernsnowconference.org/PDFs/1964Farnes.pdf ER - TY - Generic T1 - A snow course network for Alaska and the Rampart Project T2 - 32nd Annual Western Snow Conference Y1 - 1964 A1 - Freeman, T.G. KW - Networks, Snow survey AB - Snow survey courses and snow depth marker network are reported to be in use at some 49 locations throughout various river basins in Alaska. The data are to be used primarily for flood control projects anticipated by the Corps of Engineers and power development by the Bureau of Reclamation. The State Department of Fish and Game and the Forest Service are cooperating in the establishment and maintenance of the courses and other hydrological data measuring stations. New problems in snow surveying are presented in the wide expanse of Alaskan wilderness, extreme cold, bad weather and poor visibility during the winter and spring months. The actual snow measurement of low density snow on frozen ground presents a problem of redesign of sampling equipment . A gradual expansion of the network is planned for the Rampart Dam project in cooperation with the Canadian Government. JF - 32nd Annual Western Snow Conference T3 - Proceedings of the 32nd Annual Western Snow Conference PB - Western Snow Conference CY - Nelson, British Columbia UR - sites/westernsnowconference.org/PDFs/1964Freeman.pdf ER - TY - Generic T1 - Soil moisture in forecasting T2 - 31st Annual Western Snow Conference Y1 - 1963 A1 - Farnes, P.E. A1 - Nelson, M.W. A1 - Freeman, T.G. KW - Soil moisture measurement, Water supply forecasting AB - A practical and economical measurement of soil moisture and temperature of soil has been developed utilizing electrical capacitance between monel metal and fiberglass cloth and a dielectric solution for changes in temperature, for the units planted at various depths in the soil. Considerable effort has been directed towards establishing a network of soil moisture stations throughout the mountainous areas of the Western U. S. Using calibration curves, meter readings are converted to soil temperature and soil moisture. Soil moisture and temperature data are used as an index to grass forage on the cattle ranges and timber management, for potential drought or flood conditions. Graphs and tables illustrate the procedure. 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/1963Farnes.pdf ER - TY - Generic T1 - Use of snow surveys by Denver Water Board T2 - 30th Annual Western Snow Conference Y1 - 1962 A1 - Fischer, R.W. KW - Municipal water supply, Networks AB - A historical review of the Denver city water system from the beginning in 1872 with steady growth and transcontinental diversion from west to east through the Moffit Tunnel in 1936. The need for additional reservoir storage has become evident. In order to better manage the storage problem and diversions, an addition is being made to the present snow survey course network to meet the demands for more accurate streamflow forecasting. Proposed locations of courses are shown on the accompanying map of the project. 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/1962Fischer.pdf ER - TY - Generic T1 - Low-flow forecasts on the Rogue River T2 - 29th Annual Western Snow Conference Y1 - 1961 A1 - Frost, W.T. KW - Critical flows, Water rights, Water supply forecasting AB - A critical low-flow forecast of the Rogue River is developed to meet demands of irrigation district management for information as to dates they could expect the river flow to drop below 900 cfs., when pumping operations must commence to satisfy water user demands. By using the date and height of peak flow the falling limb of the hydrograph is easily constructed to the 2000 cfs., and the coded number of days to reach 900 cfs., after March 20. Three graphs are exhibited to show the relation between variables used and the array of data is shown in tables with statistical parameters. JF - 29th Annual Western Snow Conference T3 - Proceedings of the 29th Annual Western Snow Conference PB - Western Snow Conference CY - Spokane, Washington UR - sites/westernsnowconference.org/PDFs/1961Frost.pdf ER - TY - Generic T1 - Use of snow survey data by soil conservation districts T2 - 26th Annual Western Snow Conference Y1 - 1958 A1 - Fredericksen, D.C. KW - Economics, Farm irrigation, Water management AB - The farmer water-users are taking an active part in the Soil Conservation Service Districts in the Western States. A large number depend on snowmelt water for irrigation, reservoir storage, and water management. They are taking a keen interest in water supply forecast committee meetings and forecast bulletins issued primarily for localized use. These local bulletins and committee meetings show a marked economic impact on the farm crop planning, particularly when there is a short supply of water. Savings in farm operation can amount to as much as $378,850 in one year in one Conservation District by, (1) saving on land preparation, (2) selection of crops that use small amounts of water, and (3) good water management. Although this case may be an ideal situation, other Districts can show a great savings by proper farm management and water conservation through the use of the localized forecast bulletin data. 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/1958Fredericksen.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 - Frazil and anchor ice T2 - 17th Annual Western Snow Conference Y1 - 1949 A1 - Farrow, R.C. KW - Anchor ice, Frazil ice AB - Frazil ice is formed in turbulent streams when temperatures are below freezing.. Needles of ice from on the surface and are submerged by the turbulent water forming a turbid mass of ice and water. Slush ice is caused by heavy snowfall on open water that is near or below freezing point. Slush ice chokes intakes, penstocks and turbines, necessitating the closing of power facilities to clear the pipes. Experiments with steam to combat ice at intakes have proven expensive and inefficient. Compressed air forced through the water at the intakes has been effective. Anchor ice forms most rapidly on dark colored streambeds of turbulent streams on cold clear nights. Anchor ice never forms under the cover of sheet ice. Anchor ice will thaw loose and float away during days of bright sunshine and form again on very cold clear nights.Discussion by Ralph L. Parshall. JF - 17th Annual Western Snow Conference T3 - Proceedings of the 17th Annual Western Snow Conference PB - Western Snow Conference CY - Denver, Colorado ER - TY - Generic T1 - Forecast flood-seasonal runoff T2 - 16th Annual Western Snow Conference Y1 - 1948 A1 - Ford, Perry M. KW - Runoff, Snowmelt, Statistical analysis AB - A chart for forecasting the April-June discharge of the Swan River of the Flathead River Basin in Montana was prepared after statistical treatment of variables. The principal variables used were seasonal distribution of precipitation during the accumulation period and mean temmperatures during December and March. The chart involves precipitation weighted as to time of fall and the mean temperatures of December and March The chart is designed to forecast only the total April-June discharge of the Swan River.Discussion by Joseph Kittredge. 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 - Low-cost storage-type precipitation gages T2 - 14th Annual Western Interstate Snow Survey Conference Y1 - 1946 A1 - Fittinger, H.J. KW - Precipitation gage, Shielded storage gage AB - A different design of a storage precipitation gage is described and pictured. The gage is designed primarily for low altitude where freezing is not a problem. However, an initial charge of antifreeze solution could be used during winter months to insure against freezing and loss of the catch. Where rain gages cannot be attended in isolated locations this design appears to be adequate.Discussion of the gage design is presented by Ashton R. Codd. JF - 14th Annual Western Interstate Snow Survey Conference T3 - Proceedings of the 14th Annual Western Interstate Snow Survey Conference PB - American Geophysical Union, Transactions, Part I: CY - Sacramento, California ER - TY - Generic T1 - Revised procedure for forecasting the spring runoff above Fort Peck T2 - 8th Annual Western Interstate Snow Survey Conference Y1 - 1940 A1 - Freeman, D.B. KW - Graphical analysis, Water supply forecasting AB - The accuracy of the forecasting procedures for the Missouri River above Fort Peck Reservoir is shown to be improved by adding weighting factors to precipitation data and from additional sophisticated statistical methods to test the factors for correlation coefficients and also to make full use of the snow survey courses installed in the headwaters areas along the Continental Divide in 1934.Graphical solutions show the effects of the corrective methods. JF - 8th Annual Western Interstate Snow Survey Conference T3 - Proceedings of the 8th Annual Western Interstate Snow Survey Conference PB - American Geophysical Union, Transactions, Part III-C: CY - Seattle, Washington UR - sites/westernsnowconference.org/PDFs/1940bFreeman.pdf ER - TY - Generic T1 - The influence of autumn rainfall on the runoff from melting snow T2 - 7th Annual Western Interstate Snow Survey Conference Y1 - 1939 A1 - Farrow, R.C. KW - Fall streamflow, Precipitation, Soil priming, Water supply forecasting AB - A report of a study of ‘Soil Priming’ effects on seasonal runoff as related to the water supply forecasting on the Okanagan River, British Columbia. A soil moisture deficiency curve is developed from fall precipitation data and runoff data over a 14 year period (1923-37). Estimates from the curve are used to adjust the seasonal runoff in percent of normal flow. Statistical procedures are used. A table of data is exhibited and plotted graphs illustrate the effects on seasonal runoff.Discussion by R.E. Horton is included. 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 - A limit of practicable usefulness of snow surveys for forecasting runoff at Ft. Peck Montana T2 - 7th Annual Western Interstate Snow Survey Conference Y1 - 1939 A1 - Freeman, D.B. KW - Precipitation data, Water supply forecasting AB - The prediction of the Missouri River flowing into Fort Peck Reservoir presents many problems where the reservoir is 225 miles east of the nearest snow survey course. The river transverses an entirely different environment from the headwaters basins. Many unmeasured diversions are encountered as well as unmeasured tributary streams. Precipitation data appeared to show a better relation to percent normal than the snow survey data, probably due to the remote location of the reservoir and the large area in the rain fall altitudes. In order to produce a more reliable forecast from snow surveys a longer record of data is needed and considerable study will be necessary. 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 - Establishing first year-normals on the basis of accumulated showfall snd some forecasts from runoff ratios T2 - 5th Annual Western Interstate Snow Survey Conference Y1 - 1937 A1 - Farrow, R.C. KW - Statistical analysis, Water supply forecasting AB - Three snow courses (one in each area) were laid out in 1937 at Glacier in the Selkirks, at Field in the Rockies, and at Fernie in the Southern Canadian Rockies. The location are near various precipitation stations whose data can be related to runoff at higher elevations. Sampling data from the 3 courses, the method used in obtaining a tentative first year normal, the mechanics of forecasting used, and the application of the forecast to points further downstream by use of runoff ratio factors are discussed. The percentage method is compared with the density method in establishing first-year snow course normals. It is concluded that a relationship between snowfall data and runoff is evident and that precipitation during runoff does not affect runoff. A refutation by Carl Elges of the density method is contained in the discussion. (See also SIP U1695 and WSC 35-37). 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 - Snowfall and runoff in the Canadian Columbia Basin: a study to determine the ideal locations for snow survey stations T2 - 5th Annual Western Interstate Snow Survey Conference Y1 - 1937 A1 - Farrow, R.C. KW - Snow course location, Statistical methods, Water supply forecasting AB - Snow courses, representative of runoff at Golden, Revelstoke, Trail, Wardner, and Glade were located by statistical analysis. Uniformity in fresh snow density throughout the area suggested that inches of snowfall could be compared with runoff. Data on snowfall at 5 precipitation stations in the Golden area were compared with runoff at Golden during 20-year period. Similar statistical methods were used for other stations. Seven new courses were planned on the basis of these statistical analysis. New courses for the Trail and Kootenay River are planned. A location map shows the location of stations, and tables of data and graphs illustrate the procedures. 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 -