Weather modification law and the environmental effects of snowpack enhancement - Davis, R.J. (43rd Annual Western Snow Conference, 1975)
Technology for snowpack augmentation is being developed by experimental orographic cloud seeding in the Intermountain and Pacific Coast states. There are ecological, as well as meteorological and hydrological, consequences of such atmospheric water resources development. Federal and state laws establish four steps in planning and mangement which will minimize any negative aspects of snowpack enhancement. First, the National Environmental Policy Act and similar state laws require project environmental pre-assessment. There must be interdisciplinary planning and disclosure of environmental effects of large-scale governmental cloud seeding. Second, in order to comply with reporting laws, seeders must monitor projects. Obtaining data, however, is complicated by wilderness legislation. A third step is data assessment. Laws in a few jurisdictions impose upon seeders evaluation requirements. Finally, seeding programs must be altered in light of environmental data. Regulatory agencies use it to determine whether to modify operational permits or to re-issue them in subsequent years.
Keywords: Weather modification - legal aspects

Land use planning - Deets, N.A. (43rd Annual Western Snow Conference, 1975)
Utah has made an effort to utilize and develop the state's water resources. These efforts started in 1902 with passage of the Reclamation Act and continued through Central Utah Water Conservancy District formed in 1964.Because of conflicting ideas regarding development of water is is essential to develop a comprehensive land use plan.To develop such a plan an interdisciplinary team approach was used. The area was then divided into similar geologic and geomorphic characteristics. Each area was then inventoried utilizing the team.
Keywords: Land use management, Land use planning, Watershed basin analysis

Public response to proposed snowpack augmentation in the Sierra Nevada - Farhar, B.C.; Mewes, J. (43rd Annual Western Snow Conference, 1975)
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.
Keywords: Weather mods - sociological effects

Snow maps for the Canadian Hydrological Atlas - Findlay, B.F. (43rd Annual Western Snow Conference, 1975)
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.
Keywords: Mapping - hydrological data

Airflow patterns and snow accumulation in a forest clearing - Gary, H.L. (43rd Annual Western Snow Conference, 1975)
Snow accumulation and airflow patterns were measured before and after establishing a clearing 1 tree-height wide and 5 tree-heights long in a lodgepole pine forest. The long axis was normal to prevailing wind. The profile of accumulated snow, less the mean amount of snow upwind of the clearing, was compared with the streamline patterns of airflow. Snow profiles are shown for 2 years where annual accumulation varied by a factor of 2. Snow accumulation was maximum in the clearing and minimum just behind the lee clearing edge. The maximum was centered about the upwind edge of the back eddy of airflow in the clearing. The minumum coincided with the down wind edge of the same eddy. These comparisons suggest that clearings may become saturated similar to snowfence systems, and that the accumulation pattern reflects primarily wind drift of falling snow rather than subsequent erosion and redeposition.
Keywords: Drifting snow, Snow cover in forests, Snow transport distance

Upper air data as a parameter in estimating snowmelt runoff - Hannaford, J.F.; Howard, C.H. (43rd Annual Western Snow Conference, 1975)
Hydrologic models have been designed to simulate mean daily runoff on the Kings River and San Jaoquin River. These models utilize certain parameters indicating the condition of the watershed such as snow, precipitation, and daily temperatures throughout the snowmelt period. It might be desirable to determine what runoff condition would prevail if temperatures were higher or lower than average. An estimated surface temperature at the 7,000 foot elevation has been utilized. This method produces an index which is useful in estimating the effects of air temperatures, radiation and perhaps factors in priming and melting snowpacks.
Keywords: Models - hydrologic

Automated remote data acquisition - Horton, D.D. (43rd Annual Western Snow Conference, 1975)
Automation of remote data collection sites is now possible, due to reliable solid state components and other technical advances. This paper presents a methodology for determining the optimum components comprising an automated remote data acquisition system from the currently available alternatives.
Keywords: Telemetering hydrologic data

Research coordination and utilization at Lake Tahoe - Jones, J.R. (43rd Annual Western Snow Conference, 1975)
The Lake Tahoe Basin located in the Sierra Nevadas of California and Nevada is quite unique in that it brings together, many times in conflict, the snow, water, and people. With increased recreational demands and increased development, the spotlight has been on the Basin as the Tahoe Regioal Planning Agency has attempted to develop and enforce a General Plan which would allow planned growth and still adhere to environmental constraints. The Tahoe Regional Planning Agency and the Lake Tahoe Area Council, through funding from the National Science Foundation, have developed and are jointly administering the Research Coordination Unit. The primary objectives of this project are to identify research needs, coordinate research efforts, and make results readily available to governmental entities making planning and management decisions. The Lake Tahoe Area Research Coordination Board is comprised of a Governing Board and Science Advisory Panel, both with representation from various governmental, educational, and citizen oriented entities, and a small permanent staff. The benefits of this project are increased and more efficient utilization of research by government, the public, and the researchers.
Keywords: Research coordination, Research utilization, Watershed basin analysis

Measurement of snowpack wetness - Linlor, W.I.; Smith, J.L.; Meier, M.F.; Clapp, F.C.; Angelakos, D. (43rd Annual Western Snow Conference, 1975)
This paper describes three electrical methods for measuring wetness of snow: The first is based on the change in capacitance of a sample before and after freezing; the second, on the dielectric loss of a sample in a high-frequency field; and the third, on attenuation of a microwave beam while is is transmitted through the snow. The theoretical basis for these and related systems is presented, together with experimental results. Methods for calibrating the systems are discussed. The microwave system can be operated automatically in remote installations, utilizing satellite telemtry for data gathering. Three Plexiglas towers permit the transmitter (source) and two receivers to make vertical traverses, yielding a wetness profile from the amount of attenuation occurring in the known distance between the receivers. Alternatively, the source can be mounted in a tower, with spaced receivers in the snow, to yield the average wetness of the snowpack.
Keywords: Snow radiomicrowave sensing, Snow research programs, Snowpack analysis

Accuracy of snow measurements - Peterson, N.R.; Brown, A.J. (43rd Annual Western Snow Conference, 1975)
Investigation of snow measurement accuracy has been conducted by the California Cooperative Snow Survey Program at the Alpha Instrument Evaluation Site since 1965. Results of volumetric tests conducted at the site to determine snow sample tube accuracy are presented. A method to adjust manual control samples at operational automatic snow sensors in order to check telemetered data accuracy is outlined. Application of correction factors, derived from these studies, is illustrated. An adopted operational program for obtaining scheduled control samples at field sites in California is explained.
Keywords: Sampling accuracy tests, Snow sampling

Interpreting snow survey data for use in environmental planning - Shafer, B.A.; Farnes, P.E. (43rd Annual Western Snow Conference, 1975)
Historically the Snow Survey Program has been directed toward gathering and processing of snow survey data to provide timely and accurate forecasts of forthcoming water supplies. In recent years the wealth of data gathered and cataloged in this program has become of even greater value. Mounting pressures of industrial , urban, and recreational development in the foothills and mountains of the West have resulted in planners and mangers demanding more extensive climatological and hydrological information than has hitherto been available. Snow hydrologists in the snow survey program responding to this need are providing answers to many of their requests. Planners are being given help in such diverse areas as reservoir management, snow loads, snowfall, and snow depths, ski and snowmobile area evaluations, mountain hydrology, and average annual precipaitation. Much has been accomplished in the field in interpretations for planning but much remains to be done.
Keywords: Snow survey - uses for planning

Contributions to runoff from a melting prairie snow patch as traced by Oxygen-18 - Steppuhn, H.; Krouse, H.R.; Erickson, D.E.L. (43rd Annual Western Snow Conference, 1975)
Contributions to the surface runoff flowing from a melting prairie snow patch in Saskatchewan by comparing O-18/O-16 ratios of three possible water sources. At least 85%, if not 100%, of any day's runoff was traced directly to the melting snow of that day.. The remainder, if any, apparently originated as soil water which was displaced by meltwater from snow or frozen soil.
Keywords: Chemical analysis-snow, Snowmelt-research

Predicting profiles of snowdrifts in topographic catchments - Tabler, R.D. (43rd Annual Western Snow Conference, 1975)
A regression model was developed that requires only terrain data to estimate snowdrift profiles. Results from sites in Wyoming and Colorado show drift slopes to be influenced by the terrain from 45 m (150 ft) upwind to an equal distance downwind of the catchment lip. Observed drift profiles are closely duplicated when the regression equation is used to predict the slope of successive profile increments. Results are compared to those of Finney's wind tunnel experiments.The Wyoming Highway Department is presently making this analysis a part of their earthwork computer program to help design drift-free roads. Among many other possible applications is the development of criteria for reshaping strip-mined terrain to maximize on-site retention of snowfall and regulate its areal distribution. A progam listing is given for the Hewlett-Packard 9820A calculator and 9862A plotter.
Keywords: Drifting snow, Snow fence

Snowmelt lysimeter - Thompson, K.; DeVries, J.; Amorocho, J. (43rd Annual Western Snow Conference, 1975)
A snowmelt lysimeter employing a moving cylinder to isolate test snowpacks from surrounding snow has been constructed for detailed study of effects of evaporation suppressants and albedo modifiers upon snowpack properties and melt rate under natural conditions. Data will be applied to an existing mathematical model of the snow melting process in order to optimize snowpack management. Initial tests are currently being made, and measurement techniquew and operating procedures are being refined.
Keywords: Lysimeter studies-snowmelt, Snowmelt-research

Airflow and gas exchange in snow-fact or fiction - Van Haveren, B.P. (43rd Annual Western Snow Conference, 1975)
Snow physicists have paid little attention to the topics of airflow phenomena, void air composition, and gas transfer mechanisms in the seasonal snowpack. These processes have both hydrologic and biologic significance. Although recent information has been gathered on the concentrations and transfer characteristics of water vapor in s snow, these studies need to be expanded and intensified. The results from these preliminary studies appear to indicate that water vapor moves within and from the snowpack by diffusion and also by convection, and that concentrations of water vapor in the voids of surface snow layers may be strongly influenced by atmospheric conditions at the snow surface. Biological activity under the spring snowpack increases as snow and soil temperatures increase. Most of this activity is concentrated at or within a few centimeters of the soil-snow-interface. In order for organisms to survive under these conditions, the processes of photosynthesis and respiration must occur, which necessarily involves exchange of CO2 and O2.
Keywords: Snow water vapor, Snow water vapor movement

1974 Title, Contents, and Minutes (42nd Annual Western Snow Conference, 1974)

Physical characteristics of seasonal snow cover in northern Alaska - Benson, C.; Holmgren, B.; Trabant, D.; Weller, G. (42nd Annual Western Snow Conference, 1974)
The snow cover of Northern Alaska includes two distinct types which are separated by the Brooks Range. On the North side the snow has a wind-swept, continuous surface; on the south side it lies in heavily forested land with patches of wind blown snow cover occuring on lakes and swamps and on hilltops above timberline. The snow structure on the Arctic Slope consists of a hard, high density, wind-packed layer, overlying a coarse, low-density depth hoar layer. The snow structure in the valleys of Interior Alaska, between the Brooks and Alaska Ranges is characterized by low density, steep temperature gradients, and a thick basal depth hoar layer which sometimes makes up two-thirds or more of the snow pack.
Keywords: Snow cover distribution

A portable profiling snow gage - Blincow, D.W.; Dominey, S.C. (42nd Annual Western Snow Conference, 1974)
The density profile of snow packs has become of increasing interest to snow hydrologists in recent years. Isotopic profiling snow gages have produced excellent data at various snow stations; however, none of these are truly portable (at least to the surveyor on skis);A new easily Portable Profiling Snow Gage has been in use since November 1972, at the Central Sierra Snow Laboratory. Fixed tubes were placed at several locations on the snow course and the profile was measured each week at each location. During this past summer, the gage was used on the South Cascade Glacier with a Mt. Rose snow tube instead of fixed tubes.
Keywords: Snow density, Snow density equipment, Snow measurement, Snow sampling, Snow sampling equipment

Maclure glacier, California - Dean, W.W. (42nd Annual Western Snow Conference, 1974)
Maclure Glacier ia a small cirque glacier at an altitude of 3,600 to 3,800 meters near the crest of the Sierra Navada in Yosemite National Park, Calif. Maclure glacier is the southernmost (lat. 37deg 45min N.) of 4 glaciers in the United States being studied as part of the International Hydrological Decade program. From 1967 through 1972, snow accumulation and snow, ice, and firn-ablation data were collected to determine the annual ice and snow balance for Maclure Glacier. The net water balance for the glacier ranged from +1.2 meters in the heavy snow year of 1967 to -0.8 meters in the dry years of 1968 and 1972.Snow, ice, and runoff data were obtained for an approximate water budget for the Maclure Creek basin including the glacier. Precipitation, air temperature, and windspeed also were measured.
Keywords: Glaciers - research studies

Progrss in measuring snow cover from ERTS imagery - Evans, W.E. (42nd Annual Western Snow Conference, 1974)
A hybrid of digital and analog analysis techniques are being employed to determine the accuracy with which snow area and temporal change in snow area can be determined from ERTS satellite imagery. The principal analysis tool is an Electronic Satellite Image Analysis Console (ESIAC) which permits display of time-lapse sequences of color composite images on a color TV monitor. Binary snow maps are generated electronically, superimposed on the image display for any necessary human editing, them measured for area in a digital counter. Results are checked against high altitude aircraft photography.Bright snow is relatively easy to measure. Snow in shadow or illuminated at low incidence angles is harder to identify unambiguously. Several potential solutions for this problem and for the problem of snow-tree mixtures are being studied. A time-lapse movie showing a full year of ERTS imagery of a typical mountian snowfield will be shown.
Keywords: Snow cover photo analysis, Snow cover photo mapping, Snow line measurement, Snow measurement - aerial, Snow Measurement - photographic

Thermal conductivity - basis of a potential method for determining in situ snow density - Fowler, W.B. (42nd Annual Western Snow Conference, 1974)
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.
Keywords: Snow - density - measurement

South Cascade glacier: the moderating effect of glaciers on runoff - Krimmel, R.M.; Tangborn, W.V. (42nd Annual Western Snow Conference, 1974)
Runoff and water balance measurements made at South Cascade Glacier and other glacierized basins in the North Cascades demonstrate the role of glaciers in moderating runoff. The summer runoff from mountain drainage basins that do not have glaciers is highly variable from year to year. Drainage basins that have only a small fraction of glaciers have a natural variance which is considerably less. The mechanisms that cause this decrease in variance are: (1) The increased albedo of a glacier surface during years of high snowfall results in decreased ablation, hence less runoff. During years of low precipitaiton and less snowfall, much more low albedo ice is exposed and runoff is increased. (2) The release of liquid storage from within the glacier is nearly independent of climatic variations and also acts as a runoff moderate.(moderator?)
Keywords: Glaciers, Runoff

Meteor burst communications - Leader, R.E. (42nd Annual Western Snow Conference, 1974)
This paper will discuss the application of Meteor Burst Communicatios technology to remote data acquisition and control. This type of system is ideally suited for low data rate telemetry such as that encounterd in hydrological, meteorological, and oceanographic data sensing.Ionized trails in the upper atmosphere resulting from meteor bursts can be utilized to reflect or re-radiate short VHF radio messages between point-to-point stations located anywhere within 1200 miles. Reliable message exchange in excess of 100 per hour can be realized.A typical meteor burst system would consist of a base station transceiver and a central processor with a number of remote radio stations designed for data collection or external control. Operation in the Artic regions is enhanced by the auroral effects. The manner is which meteor burst operates would permit communication on auroral forward scatter.
Keywords: Telemetering - hydrologic data, Telemetering equipment

Streamflow formation in the Mistaya river basin, Rocky Mountains, Canada - Loijens, H.S. (42nd Annual Western Snow Conference, 1974)
An analysis of hydrologic information from a glacierized river basin, the Mistaya Basin, in the headwaters of the North Saskatchewan River, (244 sq km) is presented. Special emphasis is given on the contribution to streamflow from glaciers which cover 12% of the area. Analysis of the hydrologic balance of Peyto Basin shows that the glacier exerts an appreciable delaying effect on water supplied by snowmelt in the early part of the melt season. Differences in runoff between three highly glacierized subbasins in the larger Mistaya River drainage basin are discussed and explained in termms of runoff delay caused by a glacier, exposure and karst features.
Keywords: Glaciers, Runoff

An ice melt formula - Peak, G.W. (42nd Annual Western Snow Conference, 1974)
This paper is a continuation and update of the paper presented at the Wester Snow Conference in 1969. It demonstrates the development of an ice melt formula. This technique can be used to evaluate evaporation of snow fields over a wide range of temperatures.
Keywords: Atmospheric vapour pressure over ice, Ice melt formula, Water supply forecasting

Simulating runoff to the Hungry Horse reservoir of western Montana - Pearson, T. (42nd Annual Western Snow Conference, 1974)
The Streamflow Synthesis And Reservoir Regulation (SSARR) Model has been modified for use by the Columbia River Forecasting Service (CRFS) in simulating runoff to the Hungry Horse Reservoir in western Montana. Temperatures from the 10,000 foot level were used from the National Center for Atmospheric Research sources together with ororaphic precipitation from ten separate zones. Daily Evapotranspiration Index and daily melt rates also by zones are functons of the modified model.Simulted runs from 1965, 1970 and 1971 were used to verify the accuracy of the model.The improved model can be used to assess cloud seeding benefits as well as in flood control and volumetric forecasting.
Keywords: Runoff models, Snowmelt

Harvesting glacier ice - Schulz, E.F. (42nd Annual Western Snow Conference, 1974)
With seventy-five percent of the earth's fresh water supply locked up in Antarctic and arctic sheets, this source of water could be used for fresh water in water short areas.The method of transporting large icebergs by ocean tugs is discussed with expected melt rates of the icebergs due to drag friction and ocean temperatures. Power rates and speed of the tugs is computed as well as methods of tow. Methods of reclaiming this fresh water at the final destination are also discussed.
Keywords: Iceberg transportation

Computer simulation of glacier mass balance throughout an ablation season - Williams, L.D. (42nd Annual Western Snow Conference, 1974)
A computer program is described wich simulates changes in snow water equivalent or glacier mass balance over a gridded topography throughout an ablation season. Initial conditions of snow accumulation are specified by a method suggested by G. J. Young. Heat and water budgets are estimated from meteorological data (measured or hyothetical) to predict ablation on a daily basis. By careful programming it is attempted to minimize computer time while maintaining reliability for a large number of grid points. A test of the model for a 6 by 9 km area on Baffin Island is found to give adequate agreement with observations. While further tests are necessary to validate the model, it is felt likely to be suitable for a number of applications in snow hydrology and glaciology.
Keywords: Glaciers - ablation, Glaciers - research studies

A stratified sampling design for snow surveys based on terrain shape - Young, G.J. (42nd Annual Western Snow Conference, 1974)
A stratified sampling design for snow accumulation studies is described. The design is currently being used on five glaciers in Western Canada. The method can also be applied to non-glacierized basins.Difficulties of mapping snow cover distributon and of calculating areal totals of snowpack volume are discussed. Previous studies have shown that snow depths at point locations are associated with slope angle and local relief of the surface; it is argued that if depth samples are taken in areas of mean surface slope and mean local relief, then mean snow depth will be realistically defined. To this end, meaures of surface slope and local relief are generated at all grid line intersections of a square mesh (of interval 100m) covering the glacier. The glacier surface is then classified into areas which are typical in terms of these measures. Depth sampling is carried out within such 'typical' areas.A detailed discussion is given of how the method can be implemented for a study area.
Keywords: Snow cover - distribution of glaciers, Snow -measurement

1973 Title, Contents, and Minutes (41st Annual Western Snow Conference, 1973)

Avalanche studies in the San Juan mountains of southwestern Colorado - Armstrong, R.L. (41st Annual Western Snow Conference, 1973)
This publication contains an overview of the snow avalanche research activities being conducted by the Institute of Arctic and Alpine Research, University of Colorado, in the San Juan Mountains of Southwestern Colorado. The research is funded by the U.S. Bureau of Reclamation with the objective being to develop a forecast model for avalanche occurrence in an area of the San Juan Mountains being considered as a possible target area for the cloud seeding operations of Project Skywater. The field methods being used to acquire data regarding avalanche occurrence are described. In addition, research directed towards establishing an Avalanche Zoning Plan for San Juan County and the town of Silverton is described.
Keywords: Avalanche, Physical properties, Project skywater, Statistical evaluation

Snow sampling techniques on a small subalpine watershed - Bartos, L.R.; Rechard, P.A. (41st Annual Western Snow Conference, 1973)
Discusses the advantage of a transect method of snow measurements in a subalpine watershed in Wyoming. Stratified for elevation and between forest and open wind influenced areas was found necessary. It was found that snow density was uniform and only required a few measurements to define this parameter.
Keywords: Snow cover, Snow density, Water equivalent, Water supply forecasting

U. S. Forest Service claims - between the snowpack and downstream water interests - Cooley, J.R.; Mulvaney, R.J. (41st Annual Western Snow Conference, 1973)
A discussion of control and water rights in the United States. Deals primarily with the State of Colorado methods of adjudication of water rights including claims by the United States. Conflicts under state law with rights of others to divert water - a right that Colorado Constitution says will never be denied. Indicates need for comprehensive water management due to population growth and environmental concerns.
Keywords: Comprehensive water management, Water regulation, Water rights

A comparison of techniques of sampling the arctic-subarctic snowpack in Alaska - Crook, A.G.; Freeman, T.G. (41st Annual Western Snow Conference, 1973)
Description of a comparison test for measuring snow of a Bowman type Federal sampler and a technique described as CRREL method. CRREL plot was measured by digging a pit and extracting snow samples from each horizon of the profile. Provides data of the test and makes conclusions about the two systems.
Keywords: CRREL, Density, Snow sampling, Snow tube

Snow load analysis and recreational uses of snow data - George, T.A.; McAndrew, D.W. (41st Annual Western Snow Conference, 1973)
Snow loads were computed from past records and maps depicting weight of snow by elevations was developed in Nevada and Oregon. These maps satisfied needs to architects, building officials and winter recreational developers.
Keywords: Frequency analysis, Snow load

Planning for city water supplies - Hill, L.K. (41st Annual Western Snow Conference, 1973)
A discussion of the Metropolitan Water District of Southern California; how it was organized, how it operates, what has been accomplished, major problems, and current plans.It includes a brief history and statistics concerning size of members, people served and amount of water delivered.
Keywords: Critical resourse, Diminishing water, Environmental considerations, Water pricing

Developing land use goals for California - Horn, W.L. (41st Annual Western Snow Conference, 1973)
The paper identifies land use policy currently being formulated by California office of Planning and Research and provides an evaluation of feasibility of supplying adequate water of good quality now and in the future. Provides statistical information on the use of land in the 1970’s and forecasts of changing patterns. Includes data on the scope of undeveloped land in the state and those lands under discussion for inclusion in the National Wilderness Preservation System.
Keywords: Environmental goals, Land use goals, Land use management

Cloud seeding for snow augmentation: land use ramifications of residual silver iodide nucleating agents - Klein, D.A.; Sokol, R.A. (41st Annual Western Snow Conference, 1973)
Discussion of short and long term studies of silver iodide in soils, including determination of microbial silver transformation reaction, and evaluation of specific silver form and level effects on microbial activities in laboratory and field environments, microbial ability to reduce silver, together with evidence for sub-lethal effects of low-levels of silver forms and microbial decomposer processes indicate considerable more study needed.
Keywords: Cloud seeding, Microbial process, Silver iodide, Silver transformation, Snowpack augmentation

Water resource technology and supply - Ogilvie, J. (41st Annual Western Snow Conference, 1973)
A discussion of the problems a large city has supplying water to its customers both domestic and commercial. Exploration of other sources of water such as desalination, weather modification, reuse of waste water, and transport from other areas such as Canada or Alaska.
Keywords: Cloud seeding, Desalinization, Evaporation, Waste water reclamation

Mean precipitation and snowfall maps for a mountainous area of potential urban development - Schaefer, D.G.; Nikleva, S.N. (41st Annual Western Snow Conference, 1973)
As part of an environmental impact study, the climate of the mountainous areas north and west of Vancouver, Canada were studied to assess possible climatic limitations to urban development of the mountainous slopes. A model of mean annual precipitation based upon available data and meteorological theory is presented. A mean annual snowfall map is derived in part from relationships between mean annual snowfall and mean annual precipitation at various altitudes. Implications for urban planning are discussed.
Keywords: Climatic limitations, Environmental impact, Precipitation, Snowfall

The omniscent environmental impact statement - Strauss, F.A. (41st Annual Western Snow Conference, 1973)
The 1969 Federal Legislation and (in California) 1970 State Legislation made mandatory Environmental Impact Statements (EIR) on all public work projects. In 1972, the California Supreme Court, in its decision ‘Friends of Mammoth v. Board of Supervisors of Mono County’ imposed the requirement that public agencies prepare an EIR on all private (as well as public) projects having significant effect on the environment ‘for which a permit or other similar entitlement is required’. This has had impact on local government and industry unparalleled in recent history. The legislation and effect is briefly reviewed and outline is presented of guide lines for an EIR in the form of a Logic Diagram. Comment is made as to future requirements yet to come.
Keywords: Environment, Impact statement, Matrix evaluation

Evaporation losses of windblown snow, and the potential for recovery - Tabler, R.D. (41st Annual Western Snow Conference, 1973)
Paper demonstrates potential of snow fences to increase storage on wind swept areas. Rm (Transport distance) is defined and used in various snow storage formulas. Rm was found to be about 4000 feet at sites between 7000 and 8000 feet in elevation before the wind completely sublimates the snowflake.
Keywords: Snow fence, Snow transport distance, Sublimation

Water pollution potential of snowfall on spent oil shale residues - Ward, John C. (41st Annual Western Snow Conference, 1973)
Factors in concentration and composition of water pollution from oil shale residue are cumulative volume, porosity of oil shale retorting residue, soil moisture content, snowmelt rate and fraction of the snowmelt water that appears as runoff. Overland flow water quality model was developed and used successfully for runoff from rain and snowfall.
Keywords: Oil shale residue, Porosity of oil shale, Runoff, Water pollution

1972 Title, Contents, and Minutes (40th Annual Western Snow Conference, 1972)

Section 22, Snow survey and water supply forecasting of the SCS National Engineering Handbook - Barton, M.; Pearson, G.L. (40th Annual Western Snow Conference, 1972)
The Soil Conservation Service is issuing Section 22 entitled ‘Snow Survey and Water Supply Forecasting’ of the SCS National Engineering Handbook. Section 22 provides detailed information on many aspects of snow surveys and water supply forecasting. It will be useful not only for specialists in this field but also for scholars and students because it is a compilation of information not previously available in a single publication. It is available from U.S. Government Printing Office.Section 22 is divided into nine chapters. Major topics are; Data Collection for Water Supply Forecasting, Telemetry in Data Collection, Travel to Collect Data, Data Processing, Water Supply Forecasting, and Maintenance of Installations and Equipment.Section 22 is the first comprehensive text on snow surveys and water supply forecasting since Dr. J.E. Church introduced modern snow survey techniques at Mt. Rose, Nev., in 1904 to 1910.
Keywords: Snow survey references, Water supply forecasting

Renovating sewage effluent by groundwater recharge - Bouwer, H.; Lance, J.C.; Rice, R.C. (40th Annual Western Snow Conference, 1972)
In the Salt River Valley, in central Arizona, the performance of a system for renovating waste water by groundwater recharge depends upon the local conditions of climate, soil and groundwater. The hydrological conditions in Salt River Valley, central Arizona are favorable for groundwater recharge with infiltration basins in the river bed. It is estimated that tertiary treatment by this method would cost about $5 per acre foot or less than one-tenth of equivalent in-plant treatment. This would be an additional source of water to meet future agricultural and other demands.
Keywords: Groundwater, Infiltration

Coping with population growth and a limited resource - Briggs, P. (40th Annual Western Snow Conference, 1972)
A computerized system analysis, using a series of optimization and simulation models, to prepare recommendations of water allocation was developed for use in the State of Arizona. The system was divided into three subsystems; economic, hydrologic-engineering, and one which interfaces the first two. these fit together in a closed loop which can be continuously operated until all inputs are internally consistent. This method has been used to develop technical evaluations of specific areas for use by decision makers.
Keywords: Model digital, Water management

Snow, related activities and concerns of the Grand Mesa Western Colorado - Christner, J.J. (40th Annual Western Snow Conference, 1972)
Melt water from accumulated snow on the Grand Mesa, plays a very important role in the agriculture pursuits of western Colorado. The recent large increase in people engaging in wintertime on-the-snow activities has resulted in the altering of snow redistribution patterns and the changing of snow density. The effects of these changes on forest and range ecosystems is largely unknown. Further studies are required to evaluate the changes that are occurring and to develop patterns of man’s use that is compatible with the ecological systems.
Keywords: Snowmelt management, Watershed management

A wilderness snow course - Delk, R. (40th Annual Western Snow Conference, 1972)
The Holbrook Snow Course, located in the Bob Marshall Wilderness area, Flathead National Forest, Montana, has become the focal point of controversy concerning the use of motorized vehicles in wilderness areas. Travel to Holbrook was by fixed-wing aircraft and helicopter from 1951 through 1969, and beginning on March 1, 1970, by Forest Service personnel traveling to the area on skis. This paper discusses the Wilderness Act of 1964 (PL-88-577), which requires use of ‘primitive’ means of travel, and its relation to wilderness snow courses. Problems and hazards encountered during the ski trips are discussed. The importance of the snow course and the value of the wilderness resource are evaluated. A plan to move the course to another site in an attempt to consolidate administrative uses in the wilderness area is also presented. This plan has resulted in a problem of data correlation which has not yet been resolved.
Keywords: Snow survey economics, Wilderness areas

Watershed hydrometeorological data required for weather modification - Elliott, R.D.; Hannaford, J.F. (40th Annual Western Snow Conference, 1972)
The hydrometeorological data in five western mountain watersheds were reviewed and deficiencies in existing data required for planning of large scale research weather modification projects were noted. Ideally the additional data needed for each major watershed includes a base station for project control, several climate stations to record areal coverage of precipitation and standard meteorological parameters and one mountain observatory unit for the observation of special meteorological parameters and snow quality data. Studies of existing data reveals little or no tendency for snowpack to level off or to decrease at higher elevations. Estimates of ten percent increase in precipitation during the October through April seeding periods could increase the average annual runoff by 2.5 million acre feet within the five large watersheds and an additional 1 million acre feet around the periphery of these watersheds. Extending the seeding program into May and June could increase the runoff from the five study basins by 440,000 acre feet, but caution is needed in seeding during this period because of undesirable flood potentials.
Keywords: Cloud seeding, Water supply forecasting, Weather modification evaluation

Influence of late season precipitation on runoff of the Kings River - Hannaford, J.F. (40th Annual Western Snow Conference, 1972)
In the King’s River basin of the southern Sierra Nevadas, late-season, high-elevation storms are important factors in the hydrology of the area. Numerous occurrences producing from a few hundred to perhaps 10,000 acre feet or more may be expected to occur almost every year. In aggregate they may represent from five to twenty percent of the total runoff in the May-September period. While the supplemental water produced by late season precipitation cannot be accurately forecast, accurate knowledge of the quantity and timing of such supplemental flow would be valuable to the water manager. Recent studies involving weather modification during the May-September period suggest that perhaps substantial augmentation of runoff from late season storms may be a possibility.
Keywords: Cloud seeding, Spring precipitation, Water supply future, Weather modification research

The changing water resource - Henderson, T.J. (40th Annual Western Snow Conference, 1972)
It is not the basic resource, water, that is changing but man’s influence on this resource that is producing an ever-increasing change. The effects of man on natural patterns of water supply in the case of urbanization may be large inadvertent. But man’s intentional activities may improve the environment for either more direct benefit or greater aesthetic advantage. Man’s influence can improve his environment, particularly with respect to the intelligent influence on the natural patterns of supply by means of weather modification.
Keywords: Environment, Watershed management, Weather modification research

Wilderness in the National Parks - Henneberger, J. (40th Annual Western Snow Conference, 1972)
A wilderness studies program has been underway in the National Park Service since 1964 when the Wilderness Act directed the service to study all roadless areas of 5,000 acres or more in the parks and other areas of the system that existed in 1964. This would include a total of 65 areas. Public hearings have been held on 43 and up through fiscal 1972, reports on 40 of these areas have been completed. Substantial progress on the balance has been made and completion by 1974 is anticipated. To date, Congress has created wilderness units in the Petrified Forest National Park and Craters of the Moon National Monument.
Keywords: Wilderness areas

Separation of the surface and subsurface flow from snowmelt by the use of radioactive tracers - Holecek, G.R.; Moujaim, A.A. (40th Annual Western Snow Conference, 1972)
The separation of surface and subsurface flow resulting from snowmelt for a 15 acre plot in north central Alberta was accomplished by means of a radioisotope tracer. The snow cover was sprayed with 50 to 150 millicuries of Iodine-125. Surface flow retained its radioactive characteristics while the subsurface flows lost its contamination because of filtering action by the soil mantle. This method can be used to study the impact of land utilization on the hydrologic cycle.
Keywords: Flow analysis, Flow separation, Groundwater, Runoff, Snowmelt

Avalanche awareness and safety for snow scientists in the field - Hotchkiss, William R. (40th Annual Western Snow Conference, 1972)
During the winter of 1970-71, avalanches in the United States caught 58 people, buried 46, and killed 12. Snow scientists should periodically update their knowledge of how to classify avalanche events and to evaluate avalanche hazards. A practical, three-part classification of avalanches is proposed. Part I includes static observations made following the event; Part II includes dynamic observations made at the time of the event; and Part III includes genetic deductions based on a description of the meteorological background,. Evaluation of hazard is possible through careful observation of the definitive factors which cause avalanches; accumulation of new-fallen and wind-transported snow, free water percolation through the snowpack, and progressive weakening of internal layers of the snowpack. Knowledge of avalanche classification and hazard evaluation together with the use of sound judgement, should promote avalanche awareness and safety.
Keywords: Avalanche safety

Environment and the snow resource - Kahan, A.M. (40th Annual Western Snow Conference, 1972)
The concern about the environment in the snow resource is changing with the spirit of the times. This is the keynote of the seminar on ‘Environment and the Snow Resource’.
Keywords: Environment, Snow cover accumulation

Forecast study for Prairie Provinces Water Board - Nemanishen, W. (40th Annual Western Snow Conference, 1972)
The Prairie Provinces Water Board has spearheaded a study to improve and coordinate water supply forecasts for Alberta, Saskatchewan and Manitoba. Initial forecasts for the April to October period are based on winter storage precipitation data, summer rainfall and winter base flows. Further the use of percent correction factor, based on data for three integrating loss basins, significantly improved the accuracy of forecasts for the South Saskatchewan River. Extreme residuals were reduced from plus-or-minus 23 percent to plus-or-minus 8 percent.
Keywords: Forecast accuracy, Precipitation analysis, Water supply forecasting

The application of snowmelt forecasting to combat Columbia River nitrogen supersaturation problem - Speers, D.D. (40th Annual Western Snow Conference, 1972)
The problem of nitrogen supersaturation on the Columbia River which is alleged to have resulted in severe fisheries losses, is discussed. The cause of nitrogen supersaturation and its effect on fish are reviewed, and several structural solutions to the problem are presented. An effective means in reducing the problem lies in the regulation of upstream reservoirs, and snowmelt forecasting plays an important role in this regulation. Two types of forecasts are utilized, volumetric forecasts determined by multiple regression procedures, and daily simulation of runoff using the SSARR computer model. These procedures are briefly described and examples of their application in combating the nitrogen supersaturation problem are given.
Keywords: Model, Reservoir regulation, Runoff, Simulation, Snowmelt

The Labor day storm of 1970 in Arizona - Thorud, D.B.; Ffolliott, P.F. (40th Annual Western Snow Conference, 1972)
The 1970 Labor Day Storm caused more loss of human life than any other storm in Arizona’s recent history. In addition, many dwellings, roads, bridges, and other structures were damaged by the record flooding. The meteorological and hydrological features of tropical storm Norma, and the resulting damage to human, cultural, and natural resources have been documented and analyzed. Such analyses contribute to improved estimates of the magnitude and frequency of future storm and flood events, and assist engineers and planners in the design and location of new communities, drainage systems, bridges, dams, and other cultural features.
Keywords: Flood damage, Flood forecasting

South Dakota weather modification program - Williams, M.W. (40th Annual Western Snow Conference, 1972)
A description of the current weather modification program as currently being carried out in South Dakota, and how it has developed over the past 10 years.The results of early uncoordinated weather modification efforts for hail suppression and summer rainfall increase experimentation are theorized.The growth of the program from individual efforts and trials to a total Local-State-Federal cooperative effort is detailed.
Keywords: Weather modification research

Air temperature observations and forecasts - their relationship to the prediction of spring snowmelt in the Eagle River Basin, Colorado - Zimmerman, A.L. (40th Annual Western Snow Conference, 1972)
A simple temperature index to snowmelt based on daily maximum temperature, performs quite well in the Eagle River Basin In Colorado in the spring snowmelt season during clear-weather melt conditions. During weather situations where a significant change of air mass is occurring, air temperatures are likely to be a poorer index to snowmelt than during relatively stable, dry periods. Therefore, additional air temperature data for a given river basin might not significantly improve snowmelt prediction during such periods. The predictability of air temperatures in a time frame of the next several days is improving as the general circulation prognoses improve.
Keywords: Runoff, Snowmelt, Temperature index, Water supply forecasts

1971 Title, Contents, and Minutes (39th Annual Western Snow Conference, 1971)

Field performance of the universal surface precipitation gage - Cox, L.M. (39th Annual Western Snow Conference, 1971)
The universal surface precipitation gage has proved to be an excellent research tool for making ground surface measurements of precipitation, snow water equivalent, and melt rate. Experimental results indicate that the gage provides a more realistic measure of the snowmelt process than does the conventional 12-foot butyl pillow and has the advantage of providing coincident measurements of water equivalent and the volume rate of flow from the base of the snowpack. These quantities include any water added by rainfall. The universal precipitation gage appears to have excellent potential as an operational instrument because of the completeness of data obtained and the relatively inexpensive installation and maintenance costs.
Keywords: Precipitation gage, Pressure pillow, Snow pillow, Snow water equivalent

Mountain precipitation and hydrology for snow surveys - Farnes, P.E. (39th Annual Western Snow Conference, 1971)
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.
Keywords: Forest canopy, Forest cover, Precipitation analysis, Snow water equivalent

Efficiency of foliage in horizontal interception - Fowler, W.B.; Berndt, H.W. (39th Annual Western Snow Conference, 1971)
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.
Keywords: Condensation, Hoar frost, Rime ice

Advanced techniques overcome severe environment encountered by mobile communications system - Gornall, J.C. (39th Annual Western Snow Conference, 1971)
For many years, radio engineers have sought to overcome severe environmental conditions encountered in remote mountainous areas and have dreamed of a radio station which would require no access roads, no power lines, no battery charging, and after a quick, easy and economical installation, would provide extremely high reliability and require no attention for at least five years. This dream evidently has been realized in British Columbia by the development of the special VHF radio stations described in this paper. The presentation of the paper included a series of eighty colored slides illustrating the historical background of the development, a description of the radio station equipment as well as some field installations of mountain top repeaters and snow course base stations.
Keywords: Instrumentation, Telemetering equipment, Telemetering hydrologic data

A model for updating streamflow forecasts based on aeral snow cover and a precipitation index - Leaf, C.F.; Haeffner, A.D. (39th Annual Western Snow Conference, 1971)
A simple graphical method for updating streamflow forecasts during the melt season is described. The procedure, developed from data on three small forested watersheds in the Fraser Experimental Forest, is based on: (1) aerial photographs of snow cover depletion acquired during 1964-68, and (2) a precipitation index derived from April 30 storage gage measurements adjusted for subsequent precipitation input during the snowmelt runoff season. Trial forecasts with 1969 data indicate the method gives acceptable results.The 1969 melt season was a good year to test the model, since precipitation during May and June was abnormally high. Successive adjustments of the precipitation indices reduced initial forecast errors from an average 20 percent to approximately 10 percent when the flow remaining was still about 80 percent of the seasonal total.
Keywords: Precipitation analysis, Snow cover depletion, Water supply forecastinjg

Variation of snow resources with climate and vegetation in Canada - McKay, G.A.; Findlay, B. (39th Annual Western Snow Conference, 1971)
Snow survey records are analyzed in terms of the major vegetative divisions of Canada. The complex roles of relief, water bodies and forest association varieties are demonstrated and discussed as they are key factors in snow ablation, accumulation and transport. Climatic zones of the country are also considered. In mountainous and arctic areas there is insufficient basic data to permit adequate definition.Distinctive regional snow storage patterns are outlined and some implications are drawn for water resource planners.
Keywords: Ablation, Snow cover forests, Snow distribution

Comparison of runoff from a catchment snow pillow and a small forested watershed - Molnau, M. (39th Annual Western Snow Conference, 1971)
A 12-by-12 foot square pressure pillow was modified by the addition of drains to collect the snowmelt from the pillow. This meltwater was collected in tanks and monitored by stage recorders. The daily runoff amounts from the catchment pillow was compared with the mean daily runoff from a 1580-acre watershed and one of approximately 80 acres. The runoff from the pillow provided a good measure of timing of runoff from the two watersheds. A time lag of one day was found for the small watershed and 2 or three days for the larger watershed.
Keywords: Pressure pillow, Runoff, Snow pillow, Snowmelt

Development of the fulcrum weighing device for precipitation gages - Moreland, R.E. (39th Annual Western Snow Conference, 1971)
This is a report on the development and use of a fulcrum weighing device for precipitation gages. This device was designed by the Soil Conservation Service for use on the Bureau of Reclamation’s Atmospheric Water Resources Program in the Jemez Mountains of northern New Mexico.A new weighing device was developed for the precipitation gages installed adjacent to seven snow courses in the target area. This device was developed to obtain weight readings with greater ease and quicker than the manual weighing procedure and maintain the accuracy of direct weight measurements. A load cell or transducer can be added for telemetry. Measurements and results obtained from using the fulcrum device are discussed.
Keywords: Instrumentation, Precipitation gage, Snow cover accumulation

Prediction of seasonal snowmelt runoff in the Okanagan Valley - Pipes, A. (39th Annual Western Snow Conference, 1971)
The direct evaluation of groundwater recharge in the forested parts of Carrs Landing Drainage should provide a means of improving the seasonal runoff prediction in the Okanagan Valley Watershed. The evaluation of groundwater recharge based on water level fluctuations will only have a long-range forecasting utility if it can be obtained below elevation that generate the major portion of the regional runoff and if it can be obtained in advance of the winter snowmelt inflow. The direct evaluation of recharge can interpret the effect of autumn rainfall and the effects of the rate of snowmelt priming. The forecast cannot account for additional factors that will control the melt of the heavier snowpack at higher elevations. Seasonal inflow forecasting will have to rely on statistical techniques early in the inflow season, since the evaluation of groundwater recharge can only be made after the snow has melted at the 3000 foot elevation.
Keywords: Groundwater storage, Snowmelt runoff

The use of snow fences for shielding precipitation gages - Rechard, P.A.; Larson, L.W. (39th Annual Western Snow Conference, 1971)
The development and operation of a research project developed by the Wyoming Water Resources Research Institute under contract with the National Oceanic and Atmospheric Administration is described. Preliminary information on precipitation data, statistical analysis, snow drift profiles, and wind characteristics are presented. The data shows that there is a distinct possibility of shielding precipitation gages from the adverse effects of wind by using artificial barriers (snow fences).
Keywords: Precipitation gage, Snow drifting, Snow shield, Statistical analysis

Managing snow accumulation under leafless aspen to enhance watershed value - Swanson, R.H.; Stevenson, D.R. (39th Annual Western Snow Conference, 1971)
Photographic records from Streeter Basin in Southern Alberta show that non-leaved cover influences both accumulation areas and ablation rate. Snow water equivalents in small natural openings on-half to five tree heights across were one-third more than under the surrounding canopy. Large clear areas not influenced by trees of topography were generally bare.Management implications are that total clearing of aspen and establishing grass in its stead is probably detrimental. Snow that should accumulate under aspen on the ridges is trapped in depressions, becoming direct runoff upon melting. The best range and watershed management should be strip of block clearings to hold snow on ridges. This combination should yield more forage, distribute grazing animals and augment the local groundwater regime.
Keywords: Chinook winds, Hydrology groundwater, Small openings, Snow accumulation, Snowmelt management

Radio-telemetry network used by the U. S. Geological Survey for reporting hydrologic data in Western Washington - Swift, C. III (39th Annual Western Snow Conference, 1971)
This paper describes the extent of the hydrologic data telemetry network, the type and capability of equipment used for reporting and processing the data, the types of sensors being employed, and some of the many problems experienced in installing and operating the network in western Washington. The equipment was installed by the U.S. Geological Survey in cooperation with the City of Tacoma and the Puget Sound Power and Light Company. At present it consists of a computer-operated base station, two repeater radios, four remote telemetry stations reporting data from snow survey courses, and six remote telemetry stations reporting data from stream gages. The form of data reporting is analog and processing is digital.
Keywords: Hydrologic data, Pressure pillow, Snow pillow, Telemetry

Design of a watershed snow fence system, and first-year snow accumulation - Tabler, R.D. (39th Annual Western Snow Conference, 1971)
Inducing snow accumulation with fences in areas with insufficient natural barriers can materially increase total snow storage by reducing sublimative losses and by diverting snow that would be transported further downwind.This paper describes the approach used to design a snow fence treatment for an experimental watershed to test the feasibility of this form of snowpack management. A method is presented for estimating the total amount of snow available to a fence.After 9 years of pretreatment measurements, a 12-1/2 ft. fence 1300 ft. long was built on a 111-acre watershed. Peak snowpack water equivalent on the watershed the first winter after treatment was about 70% greater than predicted without the fence.
Keywords: Snow cover accumulation, Snow fences, Water management

Directions in water supply forecasting - Tarble, R.D.; Burnash, R.J.C. (39th Annual Western Snow Conference, 1971)
The efficient management of water resources has long recognized the requirement for evaluating the magnitude of the seasonal ‘water crop’. Increasing demands on the available supply and proper management of temporary over and under supply situations have demonstrated a requirement for additional information on the potential volume and anticipated distribution of the water resource. Systems which the Sacramento River Forecast Center has developed to meet these requirements and the types of information which can be derived from such analysis are discussed.
Keywords: Water management, Water supply forecasting

Snow frequency analysis for Oregon and Utah - Vance, H.M.; Whaley, R.L. (39th Annual Western Snow Conference, 1971)
Selected snow course data in Oregon and Utah was analyzed by computer using Log-Pearson Type-3 method for determining percent chance of occurrence. The characteristics of the physical location help interpret the snow frequency data. The generated data can be used to predict expected snow loads, locate potential winter recreation areas and related uses.
Keywords: Snow cover distribution, Snow water content, Snowfall probabilities

Simulation of daily snow water equivalent and melt - Willen, D.W.; Shumway, C.A.; Reid, J.E. (39th Annual Western Snow Conference, 1971)
A simulation algorithm that can predict daily snow water equivalent and delivered meltwater on-site in the Central Sierra Nevada of California has been developed. The model uses data on precipitation, snowpack condition, and snowmelt processes. The input variables are daily values of precipitation, maximum and minimum temperature, incoming short wave radiation, albedo, and vegetative cover density. The output is daily delivered meltwater on-site. Options for estimated radiation and albedo can also be used. Results of test using two years of data showed a close correlation between predicted and actual daily snowpack water equivalent and melt.
Keywords: Model, Precipitation analysis, Snowmelt research

1970 Title, Contents, and Minutes (38th Annual Western Snow Conference, 1970)

An approach to snow load evaluation - Brown, J.W. (38th Annual Western Snow Conference, 1970)
The development of the 1964 Washoe County, Nevada, Snow Load Code is presented. Comparison is made with the 1965 National Building Code of Canada, together with comments indicating the general applicability of same to other regions. A general method of evaluating snow load values is outlined, including consideration of recurrence interval. Recommendations for additional snow courses in urbanizing mountainous areas for correlation to longer term stations are set forth.
Keywords: Snow load evaluation

A snow course weighting method - Coulson, C.H. (38th Annual Western Snow Conference, 1970)
This paper describes the derivation and use of a method of combining interdependent variables into a single variable for use in multiple regression analyses. The method is statistical and not directly related to any physical parameters. Use of this method to solve a given problem requires the use of a digital computer with a plotting arm auxiliary. The combination of water equivalents at different snow courses is emphasized but the method could be extended to other independent variables. An example of weighting snow courses for a Columbia River forecast procedure is illustrated.
Keywords: Electronic computer, Statistical analysis, Water supply forecasting

The surface instrument network of the Upper Colorado River pilot project - Crow, L.W.; Chappell, C.F.; Jones, G.W. (38th Annual Western Snow Conference, 1970)
The upper Colorado River Pilot Project is sponsored by the U.S. Dept. of Interior, Bureau of Reclamation. Its purpose is to augment precipitation in a 3300 square mile area in the San Juan Mountains of southwestern Colorado through modification of wintertime cold orographic clouds. The first project phase, initiated in November, 1968, provided for installation and operation of a network of surface instruments to collect meteorological data. A network of precipitation, wind, and temperature sensors was designed to provide an understanding of the physical processes and sequence of storm events which occur in this area and to permit evaluation of precipitation augmentation operations. The paper discusses the instrument network design, procedures developed for areal distribution of precipitation, and presents examples of precipitation patterns observed.
Keywords: Precipitation gage networks, Weather modification control

Snow and reservoir management for the Columbia River treaty decision - Fisher, W.H.; Sporns, U. (38th Annual Western Snow Conference, 1970)
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.
Keywords: Flood control, Power generation, Reservoir regulation, Water supply forecasting

Forecasting a hydrograph for the Deschutes River - George, T.A. (38th Annual Western Snow Conference, 1970)
This paper explains the procedure used to forecast critical flow levels and the dates that these levels will occur on the Deschutes River at Bend, Oregon.It discusses the value of the forecast to water users in relation to their water rights, and the problems involved in reconstructing the streamflow hydrographs used in deriving the forecast equations.Examples of forecasted versus actual hydrographs for the past several years are included. The information is used by the watermaster and irrigation districts in managing the river and their water use.
Keywords: Critical flow levels, Water management, Water rights, Water supply forecasting

The automatic hydrological radio reporting network New England division, Corps of Engineers - Gray, C.H. (38th Annual Western Snow Conference, 1970)
As an integral part of a comprehensive plan of protection from flood hazards in New England area, the Corps of Engineers has designed an automatic data collection network. This radio operated network provides extensive hydrologic data including river, reservoir and tide levels, wind velocity and direction, barometric pressure and precipitation levels in five major New England river basins. At the central station the reporting network is interfaced directly with an IBM 1130 which can automatically interrogate the entire system and provides a complete printout in three minutes.
Keywords: Flood warning network, Telemetering hydrologic data

Densities of prairie snowpacks - Gray, Don M.; Norum, D.L.; Dyck, G.E. (38th Annual Western Snow Conference, 1970)
The paper is concerned with the physical measurements of the snow water equivalent of shallow prairie snowpacks under flat, highly exposed cold conditions. Consideration is given to the relationship between ‘ground catch’ and measurements recorded by shielded automatic precipitation gauges. Physical measurement of shallow packs, their distribution and retention by ground sampling techniques are discussed. Time changes in density of freshly fallen snow caused by drifting and seasonal variation in density of shallow snowpacks are evaluated. The performance of twin-probe gamma nuclear system for detecting abrupt physical changes (greater than ½ inch) in snow density within a deep profile at scanning rates up to 15 inches per minute under cold weather operation is evaluated.
Keywords: Precipitation gage, Shield, Snow density, Snow measurements

The development and application of a hydrologic model as an operational tool - Hannaford, J.F.; Bush, R.; Barsch, R.E. (38th Annual Western Snow Conference, 1970)
Describes development of a runoff simulation technique, originally prepared for use on the American River and then applied to operational problems on the Kings River watershed during the record snowmelt runoff of 1969. Includes descriptions of hydrologic concepts and processes which have been modeled, basic data which were required to achieve simulation of these processes, and characteristics of the watershed. The paper is concluded with a description of how the modeling technique was used as a management tool to provide basic information for making operational decisions in the Kings River watershed during 1969.
Keywords: Basin characteristics, Flood prediction, Snowmelt runoff, Snowmelt simulation

Snow loads for the design of roofs in Canada - Lutes, D.A. (38th Annual Western Snow Conference, 1970)
A more rational approach to snow loads for the design of roofs in the National Building Code of Canada has resulted from a ten-year country-wide survey of actual snow loads on roofs. The objective of the survey was twofold: to determine by how much average roof loads can be reduced below the level of ground loads; and to assess factors that result in the accumulation of higher loads on particular areas of various shapes of roofs from the effects of wind, sliding, etc.This paper describes the factors that affect snow loads, the survey and its results, and present requirements for snow loads for the design of roofs in Canada.
Keywords: Snow loads

Simulating snowmelt hydrographs for the Fraser River system - Pipes, A.; Quick, M.C.; Russell, S.O. (38th Annual Western Snow Conference, 1970)
The long term goal of a study presently underway at the University of British Columbia is to develop a simulation model of the Fraser River system for research and teaching purposes. The model will be used to estimate the consequences of storage reservoirs in the river system and simulate discharge from readily available meteorological data for purposes of flood forecasting and evaluating the impact of critical meteorological patterns.The study consists of two main phases: simulation of discharge from relatively small basins and routing of flows down the river channels. Techniques which are being used are described in the paper.
Keywords: Flood prediction, Model, Simulation, Snowmelt runoff

Laboratory simulation of snowmelt - Quick, M.C. (38th Annual Western Snow Conference, 1970)
Snowmelt is the major input to high flow runoff in the Fraser River system, and is necessary to have good understanding of factors effecting snowmelt before an adequate flow forecasting system can be constructed. To study the basic physics of snowmelt, a type of low speed wind tunnel has been built in which temperature, humidity and radiation can be controlled and melt rates of 16 cu. Ft. samples of snow can be measured.Results of some of these experiments are presented and the validity of such small scale tests to the calculation of melt rates in the large scale natural situations is discussed.
Keywords: Snowmelt research, Snowmelt runoff

Simulation of runoff from rain-snow basin - Rockwood, D.M.; Anderson, J.A. (38th Annual Western Snow Conference, 1970)
The Streamflow Synthesis and Reservoir Regulation (SSARR) model is designed to simulate the hydrologic processes in a watershed and hydraulic phenomena in lakes, channels and reservoirs. This presentation summarizes a report prepared for the International Hydrologic Decade which describes the streamflow synthesis portion of the SSARR model and illustrates reconstitution of streamflow resulting from rainfall or snowmelt or a combination of the two on the Willamette Basin Snow Laboratory in the Cascade Mountains of western Oregon. The watershed area was divided into five elevation bands; rainfall, snowfall, and snowpack accumulation, depletion and melt are computed separately for each band.
Keywords: Electronic computer, Model, Snowmelt runoff

Using all available hydrologic data - Russell, S.O.; Obedkoff, W. (38th Annual Western Snow Conference, 1970)
An approach to the use of both meteorological and streamflow data has been developed by S.J. Solomon et al, and applied in Labrador. In this method, a river basin is divided into a number of squares, physiographic parameters are determined for each square, meteorological data are correlated with these parameters and from the resulting equation estimates are made of precipitation, evaporation and runoff for each square. Accumulated runoff is compared with measured runoff.This paper describes an attempt to apply the method to a mountainous area in the interior of British Columbia to determine the areal variation in runoff and also to extend the method by using snow course data as well as meteorological and stream gauge data. The results are promising and the technique has important implications for data network design.
Keywords: Basin characteristics, Flow analysis, Hydrology

Variation of snow loads on ground in British Columbia - Schaerer, P.A. (38th Annual Western Snow Conference, 1970)
The snow load used for the design of buildings varies with geographical location, elevation and aspect. In 1966 observations were initiated to obtain information on the variation with elevation. The water equivalent of the snow on the ground was measured at sites having a standard exposure and at 400 feet intervals of elevation on several mountains.The maximum snow load per winter is a second degree function of the elevation. Snow loads increase at a greater rate in wet climate than in areas where snowfalls are small.
Keywords: Snow loads, Snow water equivalent

Snow survey telemetry networks and future plans - Shannon, W.G.; Freeman, T.G. (38th Annual Western Snow Conference, 1970)
Federal agencies have legislative authority which involves the development, management and use of water resources. Full knowledge relating to the water resources is required. There are large gaps in basic knowledge and ability to predict future climatic and hydrologic events. Programs costing tens of millions of dollars are planned and put into operation based on less than a desirable level of knowledge. Present hydrologic networks are not sufficient in coverage or function. The development and use of electronic telemetry provides a means of collecting ‘real time’ information. Equipment has to meet rigid specifications. Funding for data collection is piece meal -- a better system is needed.
Keywords: Snow survey networks, Telemetering hydrologic data

Development of snow load design data for the United States - Thom, H.C.S. (38th Annual Western Snow Conference, 1970)
For development of snow load data for Standard A-58 of the U.S.A. Standards Institute it was decided that the best basis for snow load should be the observations of actual weight of snow (water equivalent) in preference to depth of snow multiplied by the density. Since structures must withstand the extreme load in any year, the annual extreme value distribution water equivalent on the ground is being employed. High elevation loads are a particular problem and work looking toward solution of this problem is discussed. Results on conversion from ground to roof and the effect of roof configuration are reviewed.
Keywords: Snow loads buildings

1969 Title, Contents, and Minutes (37th Annual Western Snow Conference, 1969)

Satellite photography for snow surveillance in Western Mountains - Barnes, J.C.; Bowley, C.J. (37th Annual Western Snow Conference, 1969)
The use of satellite photography to map snow cover distribution in the mountainous regions of the western United States are described in this paper. The techniques presented for identifying and mapping snow were developed from meteorological satellite data representative of that currently being received operationally. Differences between satellite snow mapping in flat and mountainous terrain are reviewed, and the outlook for operational snow surveillance from space is discussed. A survey of snow and ice on a world-wide basis, as planned in the International Hydrological Decade, appears economically feasible only through satellite observations.
Keywords: Satellite photography, Snow cover photographs

The relationship of snowpack density and water content changes of runoff on a small watershed in Arizona - Ffolliott, P.F.; Thorud, D.B. (37th Annual Western Snow Conference, 1969)
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.
Keywords: Ablation, Snowmelt research, Snowpack density

Soil-water freezing, snow accumulation and ablation in Marmot Creek Experimental Watershed, Alberta, Canada - Harlan, R.L. (37th Annual Western Snow Conference, 1969)
Research procedures to study flow of soil water through alternate freezing and thawing temperatures are described. Freezing commences in late November or December and persists through march to as late as mid-May or early June. During ablation of the snowpack, soil-water storage remained relatively constant at the pre-freezing level although below field capacity. Transmission of snowmelt through the soil profile to the ground-water flow system was shown to be theoretically possible and evidence presented indicating that this occurred. The major period of soil-water recharge occurred from spring rains subsequent to the disappearance of the snowpack.
Keywords: Ablation, Accumulation, Snowmelt research, Soil moisture

Aerial photographs for operational streamflow forecasting in the Colorado Rockies - Leaf, C.F. (37th Annual Western Snow Conference, 1969)
A method is developed for predicting and simulating the snowmelt runoff hydrograph by using aerial photographs taken vertically, then measuring, piece-meal, the percent of the basin covered with snow on the total basin. The procedure is developed by means of empirical correlations between snow cover depletion and runoff. In addition the application is made to daily simulation of streamflow depletion-runoff relationship and can be used effectively as a basis for advanced estimates of residual volume of flow during the remainder of the snowmelt season. Photographs are taken at about 10 day intervals, with a scale of 500 feet to the inch. The confines of the basin are divided into elevation zones and totals are derived from tabulations where the snow cover depletions are summarized. Relationships between the several variables are determined by multiple regression correlations solved by electronic computer procedures.
Keywords: Ablation, Aerial photographs, Water supply forecasting

A Snowpack evapo-sublimation formula - Peak, G.W. (37th Annual Western Snow Conference, 1969)
Throughout the Rocky Mountain region, there are thousands of square miles of heavily productive watersheds lying in the alpine and subalpine zones. These areas are completely unprotected from the enormous evaporative and sublimative losses produced by wind, temperature, and solar radiation. A snowmelt runoff equation is developed using these independent variables along with soil moisture deficit and spring precipitation. The paper consists of three parts: 1) the development of evaporation and sublimation formulae; 2) automatic data processing with these formulae, wind and temperature data from Boise USWB, and Lander, Wyoming; 3) the application of this processed data to the snowmelt-runoff analysis of a watershed. Snowmelt-runoff forecasting formulae for headwater basins with alpine areas where little protection from forests is felt, must include the factors of evapo-sublimation losses along with solar radiation.
Keywords: Evapo-sublimation, Snow survey data, Solar radiation, Temperature, Water supply forecasting

1968 Title, Contents, and Minutes (36th Annual Western Snow Conference, 1968)

Forecasting short-term discharge from snowmelt - Barsch, R.E.; Burnash, R.J.C. (36th Annual Western Snow Conference, 1968)
A short term water supply forecasting procedure is outlined for the Kings River Basin, in California. Current data collected from aerial lmarkers and pressure pillows and temperature to cause snowmelt are correlated with streamflow data to produce a forecasting procedure for volume streamflow information. Correlation procedures are accomplished by electronic data processing methods for a day-to-day flow pattern or hydrograph. forecasts are updated as differences in parameter values become significant. The Kings River is used as an example and details of the procedures are illustrated.
Keywords: Short term forecasts, Snowmelt research, Water supply forecasting

A practical approach to electronic data processing of hydrologic records - Brown, R.T. (36th Annual Western Snow Conference, 1968)
A scheme is described for processing and tabulating hydrographic and hydrologic records into standard data processing procedures. Punch cards and magnetic tapes are used for river stage field data. An X-Y chart reader was used to machine read values from the Stevens A-35 river stage recorder charts, and also from rating tables for each of the stream gaging stations. Programs were prepared for complete computation of streamflow volumes, and tabulations. Hydrologic data were also programmed and processed, such as snow survey data, precipitation, temperature, etc. Fifty years of records were completely recomputed and compiled for ADP procedures for the Southern California Edison Company.
Keywords: Automatic data processing, Hydrologic data, Stream measurement

Operational forecasts of runoff for the upper American River Project - Clorety, B.S.; Hannaford, J.F. (36th Annual Western Snow Conference, 1968)
This paper described development of a computerized water supply forecasting system with day-to-day updating of forecast as data are available. The Sacramento Municipal Utility District operates this power and water supply project from the upper basins of the South fork of the American River. There are seven drainage basins involved at nine levels of probability being involved.
Keywords: Day-to-day method, Water supply forecasting

A universal surface precipitation gage - Cox, L.M.; Hamon, W.R. (36th Annual Western Snow Conference, 1968)
A universal surface precipitation gage has been developed that measures total precipitation and records the precipitation remaining in storage as snow. A 5-foot-diameter platform made of light weight concrete, is supported by a liquid-filled 100-foot coil of butyl tubing. An opening in the center of the platform allows for the collection of atmospheric melt, rain percolate and melt, or a combination of these, and rainfall. A mechanical dual-pen recorder continuously records the rate of water collected in an underground tank and the water equivalent of snow on the platform. This recording system satisfies the long-standing need for surface measurement of total precipitation, snowmelt rates, and snow water equivalent required in hydrologic research and water yield and flood forecasts.
Keywords: Precipitation gage, Snow water content, Snow water equivalent, Storage gage

Alaska telemetering network for the Corps of Engineers and the U. S. Weather Bureau - Gray, C.H. (36th Annual Western Snow Conference, 1968)
After the disastrous flood at Fairbanks, Alaska in August 1967 a flood warning system was designed and put into operation, to prevent future disasters. Studies were made of causes and sufficient remote operation electronic equipment was selected to make an efficient network of stations. The Chena and Tanana Rivers were instrumented with telemetering equipment. Stream gages for river height and temperature electronic thermometers, snow gages, all instruments were automatic and synchronized electronically for base stations and repeater stations connecting Fairbanks and Anchorage offices. All electronic equipment is of the latest solid state design, with plug-in modules for easy repair by non technical personnel. Schematic drawings show the locations of stations and necessary telemetering and repeater stations.
Keywords: Flood warning network, Telemetering equipment

Department of Water Resources activities in weather modification - Greiner, E.C. (36th Annual Western Snow Conference, 1968)
A review and evaluation of weather modification projects and activities contiguous to the State of California Central Valley Water Project through the Department of Water Resources. Reference is made to the Department’s Bulletin No. 16 series entitled ‘Weather Modification Operations in California’. These bulletins list all licensed operators, and projects descriptions occurring during one years time. Current operations in weather modification show a marked improvement in methods through the use of advanced meteorological information that is analyzed and processed for cloud seeding operations.
Keywords: Cloud seeding effectiveness, Weather modification

Regional hydrologic area study as an analysis tool in weather modification - Hannaford, J.F.; Williams, M.C. (36th Annual Western Snow Conference, 1968)
Weather modification projects representing a wide range of effort and capability have been conducted in California and central Sierra Nevada since the late 1940’s. Data from many of these projects is collected and analyzed not to their effectiveness or to evaluate rainfall or streamflow; instead, to analyze (1) outline areas of increased runoff resulting from seeding, and magnitude, (2) to identify changes in runoff in terms of target areas, and (3) to investigate possible downwind or side effects and possible inter-project effects of major magnitude which might exist in the area of regional analysis. This work was accomplished through facilities of the Bureau of Reclamation’s Project Skywater.
Keywords: Cloud seeding evaluation, Project skywater, Weather modification

Computer reduction of water records for Pacific Gas and Electric Company - Horciza, E. (36th Annual Western Snow Conference, 1968)
Digital computer data procedures are described for assembling hydrographic data for streamflow records. Detailed description of analysis theory and solutions of streamflow problems are discussed relative to graphical and mechanical procedure. The compilation of the all important annual water year streamflow figures are explained. Forms of data and graphs are exhibited to show the logical procures followed in this process to assure prompt and correct data for predicting power output and water management between reservoirs. Over 600 gaging stations were involved for more than 50 years of records.
Keywords: Automatic data processing, Computers, Hydrologic data

Regression on principal conmponents as a tool in water supply forecasting - Marsden, M.A.; Davis, R.T. (36th Annual Western Snow Conference, 1968)
This paper demonstrates the use of regression on principal components to develop prediction equations for water supply. A general description of water supply forecasting and principal component analysis is presented. Two actual examples are given, one with details of analysis procedures. Statistical procedures are presented for use with electronic digital computers for solving the multiple regression formula values of the coefficients and their significance. The details of analysis of Yakima are included in an appendix.
Keywords: Statistical analysis, Statistical procedures, Water supply forecasting

The area of maximum effect resulting from the Lake Almanor randomized cloud seeding experiment - Mooney, M.L.; Lund, G.W. (36th Annual Western Snow Conference, 1968)
A randomized cloud seeding experiment was conducted on the Lake Almanor watershed near Mt. Lassen, California, during five winter seasons, 1962-67. The target area extended approximately 20 miles east-west and 15 miles north-south, and ranged in elevation from 4,500 to 6,400 feet, MSL. Silver iodide was released from ground based acetone solution generators which were located between 6,000 and 7,400 feet, MSL. Silver iodide releases were made for 12 hour periods and these periods were subsequently divided into four weather categories, three of which together produced approximately 85% of the total precipitation, no response to the seeding was observed in the target area. In the remaining category, characterized by westerly winds and cold temperatures, the increase peaked at approximately 59% between 5 and 11 miles downwind, and averaged 27% throughout the 21 mile distance. Both results were statistically significant at the 5% level.
Keywords: Cloud seeding, Cloud seeding effectiveness, Cloud seeding evaluation, Weather modification

Some comparisons from the use of radio reporting isotope snow gages and the snow pressure pillows - Ord, M.J. (36th Annual Western Snow Conference, 1968)
A report dealing with variations in measurement of snow water equivalent received by telemetering equipment from several stations under operation by the Corps of Army Engineers at the Walla Walla District Office is presented. At remote locations on the Clearwater River in Idaho, isotope snow gages and pressure pillows had been installed and operated by telemetering equipment for five years. A brief description of the radio reporting network and preliminary comparisons of the operation of the two types of gaging apparatus is included. Comparisons are made from the standpoints of accuracy of measurement, dependability, cost of operation, and the initial cost of equipment.
Keywords: Isotope snow gage, Snow gage, Snow pressure pillow

Snow sensors in California, a progress report - Peterson, N.R. (36th Annual Western Snow Conference, 1968)
A report on the development of snow sensor installations and a description of the existing network in California is presented. General descriptions of site locations and responsible operating agencies are outlined. The history of the Department's Alpha Instrument Evaluation site in the American River Basin is reviewed. Descriptions of precipitation, wind, and temperature instrumentation for support of snow sensor evaluation studies at this site are presented. The experimental sensor installations reviewed in this report include: six 12-foot diameter pressure pillows; one 5-foot pillow; two groups of 3-foot pillows; a pressure tank; a newly developed 6-foot diameter diaphragm type gage; two pressure transducers; and associated data recording instruments. The evaluation of various types of snow sensors and recording and transmitting equipment is encouraged to insure a rapid advance to more compact and reliable operational snow sensors.
Keywords: Pressure pillows, Snow gages

A Method for integrating snow survey and precipitation data - Schermerhorn, V.P.; Barton, M. (36th Annual Western Snow Conference, 1968)
The analysis presented in this paper indicates that, in the Pacific Northwest, a combination of snow water equivalent and winter precipitation, coupled with fall and spring precipitation indexes, appears to yield better forecasts than with either index alone. The proportion of snow water equivalent and winter precipitation in each forecast relation varies with the basin involved. The proportion appears too range form 70-90 percent snow water equivalent plus 10 to 25 percent winter precipitation in practically pure snow-fed streams to 25 percent snow water equivalent plus 75 percent winter precipitation in predominantly rain-fed streams.The weighting methods retain the simplicity of the ‘index’ method of water supply forecasting while permitting easy comparison and combination of the two winter indexes. Each stream must be studied in detail in order to determine the proportion of snow water equivalent and winter precipitation. ‘Locking in’ all variables except the one being tested aids in this determination, particularly when analysis time is reduced to a minimum by computer techniques.
Keywords: Abies lasiocarpa, Forecasting procedures, Water supply

Snow surveying by electronic telemetry - Shannon, W.G. (36th Annual Western Snow Conference, 1968)
The development of better means of obtaining a complete seasons record of snow water equivalent of the snowpack from beginning of snowfall through winter and snow melt in the spring is described and illustrated. Not only is this record graphically produced at the site of measurement, but is automatically telemetered to the office and in computer symbols and recorded on tape. The pressure pillow is described and compared with a weighing storage precipitation gage. New advanced methods of the electronic circuitry from the transducers to the transmission components are discussed. The change of frequency method is matched with standard procedures. The needs of this continuous flow of data from the mountains to the forecasting office is discussed with emphasis on water management and flood control.
Keywords: Pressure pillow, Telemetering hydrologic data

A system for making remote and undisturbed measurements of snow settlement and temperature - Swanson, R.H. (36th Annual Western Snow Conference, 1968)
One difficulty in studying snow is minimizing disturbance by both instruments and observer. Temperature can be read remotely by means of a thermistor mounted on a movable platter that settles with a particular snow layer. A system is described by using light plastic platters mounted on a guide wire that enables one to determine settlement. Its unique features are that platters can be dropped and their position determined from some distance away (10-300m) and that they are relatively free to settle with the snowpack due to a liquid mercury contact with the vertical guide wire. The system resolves vertical displacement to plus or minus 0.5 cm or 0.1 percent of maximum expected snow depth, whichever is larger. Complete construction details are given by diagrams and photographs. Circuitry for telemetering the information is discussed.
Keywords: Snow research, Snow settlement, Snow temperature

California Federal-State snow sensor investigations problems and rewards - Tarble, R.D. (36th Annual Western Snow Conference, 1968)
For the past 3 winters, (1965-66 to 1967-68) the Weather Bureau, in cooperation with the California Department of Water Resources, has been conducting studies in the use of snow sensors for obtaining real time data for river and flood forecasting. Various sizes of rubber pillows, metal disks and platforms have been installed at varying exposures and elevations. This paper points out the advantages and limitations of different types of sensors and exposures in several elevation regimes in the Sierra Nevada of California. Tables and graphs illustrate the type of data collected and advantages of current information from the mountains.
Keywords: Pressure pillows, Snow gages

The effect of the wilderness law on the collection of hydrologic data - Van de Erve, J. (36th Annual Western Snow Conference, 1968)
A discussion of the effects of the new ‘Wilderness Law’ passed by Congress in 1964 is presented. This law has such drastic restrictions written into the text that programs designated to protect the area; water management, wildlife management, fire protection, pest control; are not allowed to enter the areas to carry out necessary work. Evidence of these restrictions are presented in documentary briefs submitted with this paper. References are made to 18 specific incidences of hindrance and are presented with data in tabular form.
Keywords: Hydrologic data, Wilderness areas

Evidence of persistence or cross-contamination in cloud seeding experiments - Warburton, J.A.; Young, L.G. (36th Annual Western Snow Conference, 1968)
One hundred and fifty samples collected during 1966-67 have been analyzed for silver content using thermal neutron activation methods. The samples were collected in five separate regions of the western United States. In two of the locations where extensive randomized silver iodide seeding was occurring, with seeding periods of one day, there is evidence of persistence of silver in the atmosphere in unseeded situations. Silver, in relatively high concentrations, was present in specific storms which yielded precipitation in an unseeded region. It is speculated that this silver originated in cloud seeding regions upwind of this unseeded area. Results also provide evidence that silver iodide released from the ground in one mountainous seeding area is not arriving in the target area precipitation. This is in strong contrast to results in two other similar seeding projects where high concentrations of silver are observed.
Keywords: Cloud seeding effectiveness, Cloud seeding evaluation, Weather modification

A history of the development of overshow vehicles - Wilson, J.A.; Nelson, M.W. (36th Annual Western Snow Conference, 1968)
Oversnow travel, though a minor segment of the field of transportation, is of such importance to the activity of snow surveying for water supply forecasting as to warrant documentation for historical purposes. This a history of the development of oversnow vehicles. The vehicles are categorized by track type or propulsion systems. Categories are: (1) miscellaneous and prototypes; (2) metal tracks; (3) double-belt tracks; (4) single belt tracks; and (5) propeller driven. The discussion is confined to describing the mechanical aspects of the vehicles with no evaluation in terms of performance. Pictures of thirty-six different vehicles or models are included.
Keywords: Ski doo, Snow cat, Snow vehicles, Transportation

1967 Title, Contents, and Minutes (35th Annual Western Snow Conference, 1967)

Estimating depth-load values spring alpine snowpack - Alford, D.F. (35th Annual Western Snow Conference, 1967)
An empirical relationship found to exist between integrated ramm hardness number, Rj, in Joules and Load, L, in g-sq cm at the base of the pack at the USA CRREL Goose Lake Snow Study Site is presented. It is suggested that the Rammsonde may offer a practical approach to the study of the snow water equivalent in areas where other techniques are not feasible. Considerable discussion is presented relative to highly technical difficulties of obtaining suitable snow samples in the study of snow loads of low density snow at below Zero ºC temperatures. Instrument procedures are discussed and the Rammsonde process data are plotted and tabulated. Similar data collected in Greenland studies are compared with those made in Southwestern Montana at Goose Lake. The so-called ‘PIT’ technique, where a large number of samples are taken from the walls of a pit dug to soil surface, is described. The average of a large number of samples are used.
Keywords: Snow quality, Snow research

Bridger data system multipoint snowpack thermometry - Bowles, D. (35th Annual Western Snow Conference, 1967)
A method of multipoint snowpack measurement using the Bridger Data System has been developed and tested. Data taken from a closely spaced array of thermistor thermometers has been used to delineate the snow surface and the diurnal heat wave through the snowpack. Computer plots and manual examination of temperature gradient data are two methods used to derive snow depth information. One phase of this study has been an investigation of the stability and magnitude of the air-snow interface temperature gradient, and determine if the interface temperature gradient can be used as a reliable indicator of the snow surface. The experiment instrumentation details are shown as well as plotted data of the temperature gradient as measured by the thermistor thermometers. Conclusions indicate that the theory is practical and that the accuracy of depth of snow determination is dependent on the closeness of space of the thermistors.
Keywords: Snow accumulation, Snow temperature, Temperature

The Canadian IHD program - Clark, R.H.; Fulton, F.J. (35th Annual Western Snow Conference, 1967)
Canadian efforts in hydrology have, as in most counties participation in this scientific undertaking, been stimulated as a result of the International Hydrologic Decade (1965-1974) IHD, with attention focused on the need for more complete understanding of the inter-relationship between components of the hydrologic cycle. Although Canada has been blessed with an estimated one-third of the worlds fresh water supplies, the lack of uniformity in its distribution results in problems for hydrologists and water management experts equal in magnitude to most regions of the world, since Canada’s land mass encompasses environments ranging from humid to semi-arid and arctic to temperate.The Canadian program, in addition to administrative problems being faced by the Canadian National committee, is reviewed to provide some appreciation of how Canadian hydrologists are striving to meet the challenge of the Decade Program by undertaking studies which, collectively, will cover all aspects of the hydrologic cycle.
Keywords: Hydrology research, IHD

Criteria for determining mountain snow pillow sites - Farnes, P.E. (35th Annual Western Snow Conference, 1967)
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.
Keywords: Snow pillow, Snow pillow location

Atmospheric water resources of the Wasatch Front, Utah - Fletcher, J.E. (35th Annual Western Snow Conference, 1967)
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.
Keywords: Project skywater, Weather modification

Density variation in a snowpack of Northern New Mexico - Gary, H.L. (35th Annual Western Snow Conference, 1967)
A better understanding of the metamorphic process in snowpacks must depend on the accurate measurement of many variables in and near the snow cover. The primary objective of this study was to explore sample variability in density measurements. Two procedures were used, the pit wall and 8 inch x 1-3/4 inch ID plastic and also steel samplers, samples were taken vertically through the entire depth of the snowpack with the standard snow sampling tubes. a great number of the small samples were taken at 4 to 5 inch intervals in the face of a pit dug to soil surface. All cores were taken to headquarters in tarred plastic bags and there weighed. Differences were at a minimum and largely accountable to field practices and differences in procedures. Data are tabulated for examination.
Keywords: Snow density measurement, Snowpack density

Current Corps of Engineers radio system developments - Gray, C.H. (35th Annual Western Snow Conference, 1967)
A description of the Corps of Army Engineers flood warning communication system, is presented, dealing with the river systems through the central states watersheds feeding into the Mississippi River and tributaries. Frequency modulation and ultra high frequency stations have been installed at river reporting and central collection stations along the Mississippi River and tributaries. Such a dual system affords complete coverage during disaster from rain and snowmelt conditions. this system is the backbone of the flood warning system for water management procedures for operating the many multi-purpose reservoirs and water control features along the river system. A similar system established throughout the northeastern states is described and exhibited in schematic system and map location of reporting stations.
Keywords: Flood control, Flood prediction, Radio communications systems

Atmospheric water resources research summer hydrology of the high Sierra - Hannaford, J.F.; Williams, M.C. (35th Annual Western Snow Conference, 1967)
A Progress report is presented for a hydrologic study dealing with the runoff produced by summer precipitation over the High Sierra, from the Kern River Basin north through the Mokelumne River basin. This study was necessary to complete the knowledge of the hydrologic cycle for the runoff from the Central Sierra Nevada Mountains western slope. Data are presented of precipitation and runoff data from gaging stations as shown. Runoff analysis is shown graphically covering some 35 stations for a period of 25 years, 1940-64. The time period of the year ran from the end of snowmelt to the beginning of each snow season. Items covered are: hydrograph characteristics; volume of runoff; timing; storm characteristics; and precipitation values. All items are discussed in the text of the paper.
Keywords: Hydrology flow analysis

Microwave radiometric sensing of the physical parameters of snow - Kennedy, J.M.; Sakamoto, R.T.; Edgerton, A.T. (35th Annual Western Snow Conference, 1967)
A field and laboratory measurement program sponsored by the Office of Naval Research and CRREL, is being conducted to determine the response to microwave radiometers to various snow conditions. The field portion of the program was carried out within the confines of Crater Lake National Park, with data obtained from new fallen powder snow and old metamorphosed snow. The measurements were made at three frequencies, 13.5 Ghz, 27 Ghz, and 94 Ghz, (one Ghz equals 10 to the 9th power cycles per second), with microwave temperatures recorded for both horizontal and vertical polarizations at viewing angles ranging from nadir to local horizon. Similar laboratory measurements were made of artificial snow made in an environmental chamber in which snow temperatures and moisture content are controlled. The results of these studies show that different microwave frequencies do not behave in the same manner as the moisture content of the snow. The measurement of these parameters from a remote sensing platform over broad areas of major watersheds would greatly aid in the management of water resources.
Keywords: Radiomicrowave sensing, Snow research

Improvements of forecasts by forecast experience or 'feel' - Malsor, R.E. (35th Annual Western Snow Conference, 1967)
A modification procedure for water supply forecasting is presented. The evaluation of intangible factors with apparently no mathematical evaluation numbers can be used for adjusting a computed forecast. The forecaster knows certain facts such as ‘no snow on south slopes’ -’general elevation of snow line as compared to similar years’ - ‘early spring runoff’ - knowledge of other local conditions. Such adjustments are termed the ‘feel’ of forecasting . Tables list some eleven forecasts with and without the ‘feel’ factor applied. Graphs illustrate the effects of the procedure.
Keywords: Forecast accuracy, Water supply forecasting

Effect of temperature on winter runoff - Simons, W.D. (35th Annual Western Snow Conference, 1967)
The effect of temperature on the October through March runoff of the Clark Fork River at St. Regis, Montana was examined in a preliminary manner. The runoff potential for each winter season of water years 1930 through 1963, was evaluated and compared to historical records. Temperature records for the October through March period of water years 1931 through 1960 for East Anaconda, Montana were used to develop two simple indices: (1) the minimum monthly mean temperature and (2) the number of consecutive days the maximum daily temperature was 32 deg F or lower. The critical flow of the 1936-37 year resulted from a runoff potential in the lower quartile in combination with the occurrence of record-breaking cold temperatures.
Keywords: Hydrology flow analysis, Low flows

Measuring snow depths by aerial photography - Smith, F.M.; Cooper, C.F.; Chapman, E.G. (35th Annual Western Snow Conference, 1967)
Aerial photogrammetry is used to measure snow depth over a 100 acre study basin in southwestern Idaho. This procedure was demonstrated successfully and shown that the same procedures used in modern aerial topographic mapping can be applied to snow covered terrain. However, some additional problems are introduced. A base control system is necessary to develop a point grid system for subtracting the soil surface elevations from the newly derived snow surface elevations. The latest model of aerial photo plotting machine is used for this work. Other problems arise in the photographic exposure and development film. Some difficulty is experienced with using filter lenses to bring out the definition of the snow surface of new fallen snow that appears always flat in certain lights without shadows, and wrinkled wind blown surfaces create a problem at times. Newly available data on processing equipment and computer techniques will aid materially in soling some of these minor problems.
Keywords: Aerial photogrammetry, Aerial photography, Snow measurements

Project Skywater - the Bureau of Reclamation's atmospheric water resources program - Stinson, J.R. (35th Annual Western Snow Conference, 1967)
A report dealing with the Bureau of Reclamation’s Atmospheric Resources program is presented, for practical applications of weather modification techniques for improving the water supply of the nation. Since its inception in late 1961, Project Skywater, as it is now known, has enjoyed almost a 40-fold increase in efforts embracing a broad spectrum of applied research. The operational research program is divided into three categories: field experiments, field support, and laboratory studies. Descriptions of each of the projects and some of the important results are presented. Field experiments involve investigations of orographic and convective clouds during winter and summer in six major water basins of the West. Field support of various types Is provided by three government agencies. A variety of problems is being studied in the laboratory, including instrumentation, cloud physics and evaluation techniques, many in conjunction with field experiments.
Keywords: Skywater, Weaher modification

Precipitation variations in a small forested watershed - Storr, D. (35th Annual Western Snow Conference, 1967)
Precipitation variations in a highly instrumented experimented watershed in the Rocky Mountains in Southwestern Alberta Canada are studied and illustrated. The study is pointed towards watershed management practices to evaluate and improve land management on the Eastern slopes of the Rocky mountains for better water yield. Instrumentation began in 1962 and has been in operation since that time. Methods for simplifying the measurement of many factors are described and recommendations for further studies are presented.
Keywords: Marmot watershed, Precipitation analysis, Watershed management

Quantitative analysis of snow deposition by use of models in a water flume - Theakston, F.H.; Naraine, D. (35th Annual Western Snow Conference, 1967)
Snow loads on roofs of buildings and other structures are studied by use of models of buildings under water in a flume where fine sand is added to simulate blown snow. The pattern of drifting sand in water is remarkably similar to snow deposited by wind. Researchers at the University of Guelph in Guelph, Ontario, Canada, have established laboratory procedures to study quantitatively the deposition of white sand injected into flowing water in the flume. Data and photographs are included to illustrate the quantity of the sand deposited and to qualify the changes recommended for building codes for orientation of structures and highways as well as landscaping features through the knowledge obtained form this procedure.
Keywords: Modelling snow accumulation, Snow loads, Water flume

Use of snow surveys to forecast inflow to Snake River betwween Milner and King Hill, Idaho - Thomas, C.A. (35th Annual Western Snow Conference, 1967)
Snow surveys are widely used to forecast flows in streams to which snowmelt is directly tributary, and to estimate the magnitude and duration of water supplies fed by such streams. A proposed method is described and results discussed in the text and illustrated by plotted data on graphs. The main problem is to account for the large amount of return irrigation water and the amount of water flowing from huge springs along the river banks in this reach of the river. This flow amounts to approximately 7,500 cfs, during a good portion of the year, and especially during the snowmelt season.
Keywords: Return flow, Water supply forecasting

Snow measurement accuracy in high density snow course network in Colorado - Washichek, J.N.; McAndrew, D.W. (35th Annual Western Snow Conference, 1967)
A progress report is presented on the Park Range Atmospheric Water Resources Program of the North Central Rocky Mountains in Colorado. This project was initiated by the U.S. Bureau of Reclamation to determine if the natural precipitation in the form of snow or rain could be increased in significant amounts by weather modification processes and to evaluate the benefits derived economically. The location of snow survey courses, pressure pillows, soil moisture and rain gages are shown on a location map. A discussion of procedures, schedules of measurements and results obtained during the years of 1964-65-66 is included, with tables showing the data collected. Some analysis of data is included in the text. Automatic recording pressure pillows are used in collecting data on water content of the snowpack.
Keywords: Pressure pillow, Project skywater, Weather modification

The Bridger Bowl acquisition system at Montana State University - Weaver, D.E. (35th Annual Western Snow Conference, 1967)
A method for multipoint snowpack temperature measurement using the Bridger Data System has been developed and tested. Data taken from a closely spaced array of thermistor thermometers has been used to delineate the snow surface and the diurnal heat wave through the snowpack.The thermometry technique is also used in determination of the accumulation rate of new snow and in measurement of total pack settlement. Computer analysis and plotting of the data permits easy interpretation of a variety of physical and hydrological parameters. Data from the mid-winter snowpack and the spring isothermal pack has been analyzed by the above technique.
Keywords: Hydrologic data, Snow research, Telemetering, Temperature analysis

1966 Title, Contents, and Minutes (34th Annual Western Snow Conference, 1966)

Snow Accumulation - Beaumont, R.T. (34th Annual Western Snow Conference, 1966)
A summary of the various procedures of measuring the snow water equivalent is present; the standard rain gage; the wide mouth rain gage; standard snow survey sampling tubes; large diameter Prairie sampler; shielded storage precipitation gages; radio-active snow gage; pressure pillow and pressure platform. All types are described and the various accuracy, advantages and disadvantages are discussed. Quotations are presented from the several references. The sharpness of the steel cutter on the standard snow survey sampling tube is apparently the most efficient way to increase the accuracy of measuring snow water equivalent.
Keywords: Snow density measurement, Snow water equivalent

A Hydrometeorological Analysis of a Maximum Probable Flood for the Portage Mountain Project Peace River, British Columbia - Davies, L.B.; Rockwood, D.M. (34th Annual Western Snow Conference, 1966)

Soil Moisture Measurement in Water Supply Forecasting - Fletcher, J.E. (34th Annual Western Snow Conference, 1966)
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.
Keywords: Soil moisture, Soil moisture instruments, Water supply forecasting - soil moisture

Some Physical Processes in Dry Snow as Seen in Laboratory Experiments - Keeler, C.M.; Ramseier, R.O. (Western Snow Conference, 1966)

Free Water Content of Snowpack in Subalpine Areas - Leaf, C.F. (Western Snow Conference, 1966)

The U.S. Program for the IHD, with Special Reference to Snow and Ice - Meier, M.F. (Western Snow Conference, 1966)

Trace Element and Trace Radionuclide Composition of Snow and Rain - Perkins, R.W.; Engelmann, R.J. (Western Snow Conference, 1966)

Radiation Instruments - Seaders, J. (Western Snow Conference, 1966)

Gamma-Transmission Profiling Radioisotope Snow Density and Depth Gage - Smith, J.L.; Willen, D.W. (Western Snow Conference, 1966)

Preliminary Investigation of Snow Accumulation and Melting in Forested and Cut-over Areas of the Crowsnest Forest - Stanton, C.R. (34th Annual Western Snow Conference, 1966)
An analysis of the effects of vegetation changes on water yield from block-cut and un-cut timber areas. Snow accumulation and water content are measured by snow survey course and standard sampling procedures. Courses were strategically located as to cut and un-cut areas on different slopes, aspect and altitude. An attempt is made to establish a pattern of snow accumulation and melting in adjacent cut-over areas and un-cut areas with regard to aspect. Details of methods are explained and the data collected are analyzed in the summary of tables and graphs.
Keywords: Forest cutting, Forest management snow accumulation, Snow accumulation, Snowmelt

Preliminary Investigation of a New Generator for Silver Iodide Using Isopropylamine as the Carrier - Steele, R.L. (Western Snow Conference, 1966)

Precipitation Gages - Types, Methods and Uses - Warner, O.R. (Western Snow Conference, 1966)

Determination and Uses of Best Individual Sampling Points on Individual Snow Courses - Wilson, J.A. (Western Snow Conference, 1966)

1965 Title, Contents, and Minutes (33rd Annual Western Snow Conference, 1965)

Snow accumulatin and melt in relation to terrain in wet and dry years - Anderson, H.W.; West, A.J. (33rd Annual Western Snow Conference, 1965)
A report of an analysis of snow survey data from 163 snow courses in the Central Sierra Nevada in California is presented. The analysis uses factor analysis and principal component regression analysis and includes recommendations for the location of snow survey courses that will better fit the terrain and produce better analysis of runoff. Definitions of 37 variables considered in the analysis are tabulated with symbols, means and standard deviations. Snow water equivalent for March 1, April 1, and May 1, for the years of 1958, 1959, and 1960 were used as dependent variables. The principal components of analysis were made to answer two questions, (1) what is the relation of snow to simple terrain variables, with respect to different years; (2) what factors contribute most towards explaining differences in snow between snow courses. The text describes electronic computer readout tables and graphical representation of data relationship, also factors related to the best probable location of snow survey courses.
Keywords: Research, Snow course location, Snow survey courses

Mt. Hood pressure pillow snow gage - Beaumont, R.H. (33rd Annual Western Snow Conference, 1965)
At Mount Hood, Oregon the Soil Conservation Service has developed and conducted evaluation tests of the pressure pillow approach to measuring the water content of the snowpack. The evaluation has indicated this method to be a practical and accurate method of measuring the equivalent water content of the snow. Installation procedures are described and shown. Comparisons between snow water equivalent by pressure pillow data and snow sampling are tabulated. A schematic diagram is shown of the recording and telemetering devices by which a continuous record is made of the snowpack accumulation and ablation; thus providing accurate data for streamflow forecasting and snowmelt computations. Wen installed above avalanche terrain such data would be valuable for avalanche prediction and safety control.
Keywords: Avalanche control, Instrumentation, Snow pillow, Snow pressure pillow, Telemetry

Snow compaction method for the analysis of runoff from rain on snow - Bertle, F.A. (33rd Annual Western Snow Conference, 1965)
A description of a water budget method used in inflow design flood studies to account for the effect of a fresh snowpack on the runoff from rain and snowmelt in the mountainous areas of the western U.S. is presented. The parameters used in the method were derived from a laboratory experiment and were checked by analysis of a large flood in California. The unique feature of the method is the evaluation of the amount of compaction (or shrinkage) in a fresh snowpack that results form the metamorphosis of the snow crystals when water is added. The snow crystals in a fresh snowpack undergo changes, as free water is added, that results in a shrinkage (or compaction) of the snowpack. Free water is retained in the snowpack until the threshold density is attained. Subsequent melting releases this free water. The procedure described, which uses a water budget based on the concept of snow compaction and a threshold density, has been a valuable aid in our design flood studies to estimate runoff from a design condition of warm rain on a relatively fresh snowpack.
Keywords: Analysis, Floods, Runoff, Snowmelt, Snowpack

Telemetering precipitation gages for remote areas - Castle, G.H. (33rd Annual Western Snow Conference, 1965)
The precipitation gage described is designed especially for use in remote areas where precipitation occurs as rain, snow, or a combination of both, and where accumulation may be 100 inches or more between visits, which may be made only once or twice a year. Design emphasis has been on simplicity and reliability in order to provide a system which can be maintained with a minimum use of highly skilled personnel. A gas bubble system is provided to assist in mixing the precipitation with an initial charge of ethylene glycol to inhibit freezing and help melt incoming snow. Towers are designed for maximum strength combined with lightweight and easy installation. The radio communication system which provides on-call operation and uses solar cells to trickle charge the battery power supply is described. Operating problems and site selection are discussed.
Keywords: Instrumentation, Precipitation gage, Telemetry

Estimating precipitation on a remote headwater area of western Alberta - Curry, G.E.; Mann, A.S. (33rd Annual Western Snow Conference, 1965)
An extensive network of storage precipitation gages covering the upper reaches of the Saskatchewan river system is described in detail. Recent developments have increased the network to include snow survey courses in the higher elevations. Analysis of existing records has made possible the adjustment of data for under-catch at the storage gages, due to wind effects. Normal isohyetal maps covering the area have been constructed. Double mass diagrams and statistical methods were employed for this adjustment of data. Precipitation elevation relationships were also taken into account.
Keywords: Precipitation data analysis, Precipitation gage network

Application of radar to snow surveying - Grant, L.O.; Marwitz, J.D.; Thompson, C.W. (33rd Annual Western Snow Conference, 1965)
Many problems exist in the use of radar for snow surveying and considerable research is being carried on in several countries. However at the present time many valuable factors can be measured and are described: onset time ; duration; intensity with time; direction of movement; rate of movement variation with the snow area; total snowfall and probably some information on size and shape of particles. With most equipment currently available, the maximum usable range for most snowfalls of the type experienced in the Rockies is in the range of 5 to 10 miles. Scope integration techniques are available to integrate accumulations over moderate sized watersheds. Radar can be particularly valuable in determining the representativeness of spot snow tube or pillow observations. Radar can also provide a unique tool for summarizing the rate of accumulation at all stages of snowpack developments. Formula development and data are shown in the text.
Keywords: Radar, Snowpack measurements

Evaluation of weather modification - Kahan, A.M. (33rd Annual Western Snow Conference, 1965)
A review of various procedures of evaluating the effects of weather modification operations used in past years is presented. Indications are the operators have made elaborate claims by simple comparisons of precipitation data from the target area after seeding and the average precipitation from past years of record. In some cases average isohyetal maps have been used. Such tests are thought to be extremely insensitive to show the desired effects. Statistical methods using multiple regression analysis and based on resulting inflow to reservoirs or streamflow is more practicable and protects against bias. With all evaluations certain assumptions must be made, either statistical, or physical processes. Seven necessary assumptions are listed for consideration. Reference is made to reports by the advisory Committee on Weather Modification and the National Science Foundation Reports on weather modification, of which 195 references on the subject are listed.
Keywords: Evaluations, Weather modification

Research on snow hydrology - Kelley, L.L. (33rd Annual Western Snow Conference, 1965)
A discussion of hydrologic factors involved in producing snowmelt runoff towards water supply or flood development is presented. Forecasting methods and forecast accuracy are questioned with a plea for additional research into the possibility of measuring all factors involved more accurately. The lack of public knowledge as to the cost of water supply and the need for more understanding should be overcome. More basic data can be collected from isolated locations by instruments coupled to modern telemetering equipment. Money for such an elaborate network of stations could be obtained by sufficient publicity and a better understanding of the needs and cost of fresh water throughout the nation. More accurate forecasts could be assured by the inclusion of accurate and more basic data.
Keywords: Economics, Research, Snow hydrology

National forest water yield management in alpine and sub-alpine area - Lonberger, T.E. (33rd Annual Western Snow Conference, 1965)
A program of barometer watersheds will provide the basis for: (1) determining the effect of management practices on hydrologic behavior, (2) developing and refining watershed precipitation, (3) actual performance. The Lake Creek Barometer watershed is described as an alpine and sub-alpine watershed. The proposed instrumentation of this watershed to measure hydrologic factors is explained. The water yield improvements which may be used on the watershed are outlined. These include improvements in water quality, water yield, and water yield timing. The barometer watershed program will determine the feasibility of using techniques originated by research on a project basis. It will also provide a basis for appraising cost-benefit relationships.
Keywords: Watershed management

Mountain versus sea level rainfall measurements during storms at Juneau, Alaska - Murphy, T.D.; Schamach, S. (33rd Annual Western Snow Conference, 1965)
Rainfall intensity measurements are made at 3400 feet above sea level on Mount Juneau and at sea level at Juneau, Alaska. Three and six hourly amounts are compared and shown in tabulations. A description of meteorological and topographic elements in the area is presented. Recording gages designed for the work are described, also operation and installation. Conclusions indicate that the normal annual precipitation at the 3400 foot elevation site is about 3.27 times that at sea level and probably about 285 inches.
Keywords: Instrumentation, Precipitation gages

Legal aspects of weather modification - Oppenheimer, J.C. (33rd Annual Western Snow Conference, 1965)
Man's interventions in Nature's atmospheric process result in interventions in his socio-economic, political and legal processes. The legal aspects of weather modification are not as tangible as water rights legal rules and regulations. Although 22 States have regulations dealing with weather modification, there have been only 6 court cases on record of which 5 were decided in favor of the weather modification operator. These cases are explained in the text of the paper. Attempts are underway to set up State, intra-State, and Federal regulations to govern and license weather modification operators either for profit or research.
Keywords: Legal aspects, Weather modification

Some economic aspects of weather modification - Rapp, R.R. (33rd Annual Western Snow Conference, 1965)
In considering the modification of weather, two obvious but easily under emphasized, necessities are (1) to set forth clearly and completely the nature of the need that is being filled and (2) to align planning with forecasting. An illustration is given of situations which augmentation of rainfall would and would not be prudent. Another shows that actually controlling the weather would differ in utility from merely precipitating a larger fraction of water from clouds than nature would.
Keywords: Economics, Weather modification

Role of snowmelt and snowpack storage in production of runoff on Feather River Basin during December 1955 flood - Riesbol, H.S.; Hunsaker, L.M.; Mahoney, D.G. (33rd Annual Western Snow Conference, 1965)
An evaluation of snowpack and snowmelt factors effecting flood producing runoff volumes on the Feather River, California during December 1955. Basic data include a description of weather occurrences, snowpack, and watershed conditions together with potential snowmelt on snowpack compaction densities. Seven potential factors are listed for snowmelt equation, to obtain daily volumes of runoff in inches per day. The basin is divided into 100 foot elevation zones to assess the basin constants according to forest cover, also to form a basis for computation of the main snowpack area when the threshold density of 45% is reached and the lip-drainage at the edge of the pack is in progress. Resulting computations are shown in tables and graphs together with conclusions.
Keywords: Floods, Snowmelt analysis, Snowmelt floods

Snowpack, precipitation and water supply forecast outlook for western United States 1964-65 season - Shannon, W.G.; Christensen, E.G. (33rd Annual Western Snow Conference, 1965)
Shannon: The exceptionally heavy snowpack of the 1964-65 season is described with data in the text, accompanied by a series of 24 color slides of snow conditions at snow survey courses (not duplicated in the paper). Reservoir storage as of April first in the Western United States is shown graphically and in tabulation for large reservoirs. Prospective streamflow for the April-September runoff period is depicted on a composite map of the Western states.Christensen: A description of weather conditions and precipitation patterns for the 1964-65 season is presented in the form of isohyetal maps of the western states, covering 3 separate periods; October-January; February-March; and October-March. A fourth map shows the percent of average forecast of streamflow for the water year. Some facts relative to the Christmas flood 1964 of Northern California and Western Oregon are presented.
Keywords: Analysis, Flood damage, Precipitation, Snowpack, Water supply forecasting

Physical aspects of weather modification - Squires, P. (33rd Annual Western Snow Conference, 1965)
Successful weather modification (cloud seeding or rain making) is brought about by either of two processes. (1) by coagulation of moisture droplets in the cloud by use of pulverized dry ice, or (2) by use of silver iodide smoke particles that have the property of nucleating ice particles in the clouds. There must be abundant moisture or moisture laden clouds in order to produce artificial rain or to trigger the process of rainfall. Research dealing with the physical properties of the most likely cloud formations and atmospheric conditions for successful weather modification has been carried on in the past, is still continuing, and must be extended into the future.
Keywords: Research, Weather modification

Soil moisture data as a forecasting variable - Stockwell, H.J. (33rd Annual Western Snow Conference, 1965)
A review of experiences with soil moisture stations using Colman Units over a ten year period in mountain areas of the Western States is presented. The purpose of the units is to obtain data on soil moisture conditions under the snowpack and use such data as a forecasting variable in relation to snow water content. The installations have been reasonably satisfactory from a mechanical standpoint; that is, they have performed generally without failure. One of the problems has been a satisfactory operational procedure for converting resistance readings from the units into a measure of soil moisture. As a forecasting variable, the value of soil moisture data is still open to question. In some locations soil moisture data has been of definite value. Guidelines for future installations and continued tests are suggested.
Keywords: Soil moisture measurement, Water supply forecasting

Engineering aspects of weather modification - Zoff, D.O. (33rd Annual Western Snow Conference, 1965)
Engineering problems associated with the conception, design, field operations and data processing of weather modification programs. Examples taken from the Bureau of Reclamation program at Steamboat Springs, Colorado, with particular emphasis on snowrate sensor and diffusion instrumentation.
Keywords: Engineering aspects, Weather modification

1964 Title, Contents, and Minutes (32nd Annual Western Snow Conference, 1964)

Evaporation from a winter show cover in the Rocky Mountain Forest zone - Bergen, J.D.; Swanson, R.H. (32nd Annual Western Snow Conference, 1964)
Evaporation from a snowpack during winter temperatures is measured in an attempt to satisfy a theoretical energy balance formula of factors involved. Field laboratory equipment is used to test the theoretical computations. Formula derivation and data from field tests are shown. Explanations of the methods and procedures are discussed together with an analysis of the problems.A discussion by Mr. David M. Rockwood substantiates the theory involved and suggestions are offered.
Keywords: Evporation, Research, Sublimation

Large scale atmospheric circulation affecting floods on the Fraser River - Bruce, J.P. (32nd Annual Western Snow Conference, 1964)
A discussion of meteorological conditions existing in the upper air masses prior to and during flood periods of the Fraser River in British Columbia, along with ground observations is presented. Prolonged periods of below freezing temperatures dragging into late spring and then sudden rises in temperature are the main causes of flooding on the Fraser River. Conclusions are drawn to show the need for more detailed research into long term (30 to 90) day weather forecasting, especially temperature changes, for predicting flood stages downstream. Maps, weather charts and tables illustrate the meteorological conditions pertaining to flood periods.
Keywords: Flood, Meteorology, Research program, Snowmelt

An economical total precipitation telemetering system - Chadwick, D.G.; Pearson, G.L. (32nd Annual Western Snow Conference, 1964)
A progress report is presented dealing with a telemetering system for collecting precipitation data from remotely located shielded storage precipitation gages in Utah. The system consists of a large capacity rain gage, charged with anti-freeze solution and mounted on a tower with shield. The gage is supported on a central spring support with potentiometer attached for varying the frequency of a battery operated transistor radio transmitting system. The radio is read by over-flight airplane 5000 to 7000 feet above the instruments. The present system is in continuous operation; however an 'On Call' system is being developed and would be triggered by operation from the airplane. Successful operation data are exhibited in three graphs. Cost estimates are included with pictures and schematic diagrams of the system are shown.Discussion by Glenn H. Castle.
Keywords: Precipitation gages, Telemetry

Spillway design for the proposed Rampart Canyon dam - Duncan, W.W. (32nd Annual Western Snow Conference, 1964)
Hydrologic data pertaining to the 200,000 square mile Yukon River basin above the proposed Rampart Canyon Dam in Alaska are analyzed for maximum possible flood to be used in spillway design. Short periods of records from a minimum number of stream gaging stations and climatological stations are utilized. Snowmelt equations developed by the Cooperative Snow Investigations program of the Army and Weather Bureau are applied. Probable maximum precipitation theories developed by the hydrometeorological section USWB are used on the 21 principal tributaries, to determine the possible maximum flood. All data was processed by electronic digital computer to develop the storage and flood routing equations. Tables and graphs illustrate the reconstructed hydrographs.Discussion by R. E. Lindgren.
Keywords: Research, Snowmelt, Spillway design

Fisheries management of Yellowstone Lake, Wyoming, as related to water supply forecasting - Farnes, P.E.; Bulkley, R.V. (32nd Annual Western Snow Conference, 1964)
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.
Keywords: Fisheries management, Water supply forecasting

A snow course network for Alaska and the Rampart Project - Freeman, T.G. (32nd Annual Western Snow Conference, 1964)
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.
Keywords: Networks, Snow survey

Development of a digital river basin model - Hannaford, J.F. (32nd Annual Western Snow Conference, 1964)
A new approach to developing a water supply forecasting procedure is presented. Use is made of an electronic computer programming for 20 years of records and including at least 9 variables consisting of streamflow by months, precipitation by months and antecedent streamflow at six gaging stations. Two river basins were selected to try the system, one of low elevation headwaters where rainfall is the predominant source of supply, and a second with high elevation where the source of supply is largely from melting snowpack. These basins were to represent the digital model. The general equation: Inflow minus outflow equals change in storage, was expanded and used as a basis for computation of factors for the model basin.
Keywords: Computer, Simulation, Water supply forecasting

A proposed snow course and meteorological network for the Columbia Basin in British Columbia - Hunter, H.I. (32nd Annual Western Snow Conference, 1964)
An evaluation of the existing network of hydrologic data collecting stations in the Columbia Basin is made. In view of recent increased needs for forecasting water supply volumes to be regulated behind large dams and great reservoirs requires more detailed data. Recommendations are made for expanding the existing network.
Keywords: Networks, Snow courses, Snow surveys

Relative importance of weather factors creating slab avalanches in Colorado - Judson, A. (32nd Annual Western Snow Conference, 1964)
Slab avalanches experienced at Berthoud Pass, Colorado are described and classified into categories. Weather factors involved in the formation of slab avalanches are delineated. Avalanche information and causal factors are listed in tables together with text narration. Wind velocity and persistence during and after snowfall is shown to be the most important factor involved.
Keywords: Avalanches, Research

Relationships between snow survey and climatological measurements - McKay, G.A. (32nd Annual Western Snow Conference, 1964)
Snow survey data on the Canadian Great Plains are compared with snow precipitation measurements made at meteorological stations in the same area. The data are found to vary with the exposure of the rain gage location and or exposure of the snow course location. Net evaporation of the shallow snowpack is explored. Degree-day snowmelt relationships are based on maximum daily air temperature. Seasonal variability controlled by 'Threshold Temperatures' (that temperature above which melting tends to occur and below which melting is not likely to occur). These computations gave good results in relation go the snowpack budget.Discussion by Donald W. Kuehl.
Keywords: Meteorology, Prairies, Snow surveys, Temperatures

A search for the least common denominator of runoff forecasting - Mitchell, W.B. (32nd Annual Western Snow Conference, 1964)
A discussion of the various factors involved in water supply forecasting is presented with emphasis placed on present day concepts of possible ways to improve basic data collection methods. An appeal is made for expansion of networks of all types of factor measuring stations, towards an ultimate aim of obtaining accurate data of all factors from water producing weather, consumptive uses and return flows for further use.
Keywords: Water supply forecasting

The little used third dimension - Peck, E.L. (32nd Annual Western Snow Conference, 1964)
A brief review of papers presented at the Western Snow Conference over the past 10 years on statistical approaches for solving problems in snow hydrology. Seasonal and long-term variations in high elevation - low elevation ratios or winter precipitation amounts for selected stations in the western states are analyzed. The possible effects of such fluctuations on the indices commonly used in snow hydrology studies are discussed.
Keywords: Water supply forecasting

1963 Title, Contents, and Minutes (31st Annual Western Snow Conference, 1963)

Operational forecasting of the day-to-day runoff in the Feather River Basin - Arvola, W.A.; Raimundo, A.L. (31st Annual Western Snow Conference, 1963)
A runoff forecasting procedure has been developed utilizing knowledge acquired in sow research in the past 10 years. A weakness of the method is that temperature forecasts can not yet be made for periods of 5 to 30 days in advance. For several snowmelt seasons, the snowmelt was determined from actual temperature data using a simple temperature versus melt relationship. Temperature was determined by averaging data for seven index stations ranging in elevation from 2710 to 5850 feet. Reconstitution of the snowmelt hydrograph for the Feather River at Oroville was made for the snowmelt season of 1952 and 1958. Aerial reconnaissance of the basin periodically during the snowmelt season will provide useful data on the retreat of the snow-line during the melt season. Maps and charts illustrate the procedure.
Keywords: Daily forecasts, Water supply forecasting

Avalanche control on highways - Atwater, M.M. (31st Annual Western Snow Conference, 1963)
A summarization of avalanche control needs and procedures for structures, winter sports areas and trans-mountain highways is presented. A description of a high altitude mining company avalanche control program is included. Comparisons of protection procedures are made and the economics of costs versus benefits derived are analyzed. Five elements of avalanche control are outlined and applied to practical problems.
Keywords: Avalanche control, Avalanche research

Snow sampling results with differing snow samplers - Beaumont, R.T.; Work, R.A. (31st Annual Western Snow Conference, 1963)
A report of field tests of snow sampling is presented, using same and different cutters, and three different types of tubes. The Feral Standard duraluminum tubes; the Bowman Plastic tubes and the Rosen thick wall aluminum tubes with smooth couplings. Data from 150 paired samples is analyzed in the test. Comparisons of water content data taken with the three different tubes varied in some respect, however in most cases the Federal sampler showed a greater amount, especially in snow of 70 to 80 inches deep and 40 percent density, where the tubes had to be rotated to cut the packed snow and ice. The inspection ports of the Federal tubes were found to be sufficiently large to scoop in sufficient snow to make the difference, while the 5/16 holes in the Bowman and Rosen did not seem to collect snow. The inside diameter of all cutters was checked and found to be very close to the standard 1.485 inches. The Rosen sampler was heavy and awkward. The Bowman sampler was difficult to drive in deep, dense snow due to the large couplings.
Keywords: Accuracy of snow samplers, Equipment testing, Plastic snow tubes, Snow samplers

Soil moisture in forecasting - Farnes, P.E.; Nelson, M.W.; Freeman, T.G. (31st Annual Western Snow Conference, 1963)
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.
Keywords: Soil moisture measurement, Water supply forecasting

Use of Lake Roosevelt storage to lower river temperatures - Kramer, H.A.; Corley, J.P. (31st Annual Western Snow Conference, 1963)
A discussion of procedures used to lower the temperature of the water in the Columbia River below Grand Coulee Dam by releasing water from lower, cooler levels of the reservoir. This process improves the economics of using the cool water for downstream plants and also improves the fish habitat during the warm months of the year. Graphical analysis of thermoclines of the reservoir waters above the dam makes possible this operation.
Keywords: Water temperatures

Snowfall extremes in the Western United States - Magnuson, M.D. (31st Annual Western Snow Conference, 1963)
A summary and meteorological discussion of snowfall records covering the eleven western States, as extracted from U.S. Weather Bureau records. Tabulations of data show greatest fall in 24 hours. Maximum monthly totals and probability of occurrence of dates, and amounts. First fall and last fall with amounts and probability of occurrence.
Keywords: Extremes, Snowfall probabilities, Statistics

Design, maintenance and operation of a trans-Sierra highway, California - Nicholson, R.I. (31st Annual Western Snow Conference, 1963)
A discussion is presented of the various highway design problems that aid for economical maintenance of snow removal, avalanche control on interstate highway through the mountains. Grade separation and route selection is stressed for avalanche control with traffic on both sides of canyons.
Keywords: Highways, Snow removal

Snowpack evaporation factors - Peak, G.W. (31st Annual Western Snow Conference, 1963)
A technical discussion of a water supply forecasting procedure utilizing snow water equivalent, soil moisture and spring precipitation to obtain the first estimate of volume runoff. A process of 'Successive Approximations' is employed to use the effect of total wind movement at the 750 millibar level, winter temperature, radiation, and hours of sunshine. A series of graphs are included to illustrate the procedure. Some interesting tests are cited relative to winter evaporation of ice and snow.
Keywords: Evaporation, Sublimation, Water supply forecasting

Snow problems on mountain highways in Washington State - Stackhouse, J.L.; Weber, F.R. (31st Annual Western Snow Conference, 1963)
Highway snow maintenance problems are discussed with emphasis placed on avalanche control, flood washout and earth and rock slides along with extreme snowfall rates accompanied by high winds. Problems are overcome with corrective measures at bottleneck locations, adequate snow removal equipment, emphasizing properly trained and dedicated operators of this equipment.
Keywords: Highways, Snow removal

1962 Title, Contents, and Minutes (30th Annual Western Snow Conference, 1962)

Use of snow surveys by Denver Water Board - Fischer, R.W. (30th Annual Western Snow Conference, 1962)
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.
Keywords: Municipal water supply, Networks

Measuring snowpack profiles with radioactive sources - Gay, L.W. (30th Annual Western Snow Conference, 1962)
Use of both gamma and neutron probes in appraising density of the snowpack is described, including some interesting effects in ice layers on density measurements. Data from the Mt. Rose snow sampling tube showed a smaller density than the readings made with the P-20 Gamma Probe. Data was also compared with readings made with a Nuclear-Chicago Model P-19 subsurface soil moisture probe and the SIPRE 500 cc. density sampling tube. All probe measurements were made from within an 11/2 inch aluminum tube.In discussion Mr. V.E. Penton mentions the importance of more development work of the gamma and neutron probes for scientific research in snow density studies. He also points out that trouble can occur in using a metal casing for the probes, such as the condensation of excess moisture on the inner surface of the metal tubing.
Keywords: Radioactive probe, Snow density

A telemetering installation to report Columbia River data by radio - Kramer, H.A.; Rand, J.L. (30th Annual Western Snow Conference, 1962)
An elaborate telemetering system for transmitting hydrographic data along the Columbia river is described. The need of accurate up-to-the-minute streamgage data and water temperatures are explained. Sophisticated electronic equipment is pictured and schematic diagrams are displayed.A discussion by Mr. Norbert Leupold presents further refinements in telemetering devises, showing automation of river flow control equalizers through the sue of electronic computer is depicted and illustrated.
Keywords: Hydrologic data, Radio, Telemetry

Improving water supply forecasts by limiting techniques - Kuehl, D.W. (30th Annual Western Snow Conference, 1962)
Water supply forecasts computed by objective procedures can be improved by modification prior to release by using methods based on several relationships. These techniques identify the forecasts which have a great probability of large errors and provide a basis for subjective quantitative adjustment. The relations are (1) adjacent basin plots, (2) carryover plots, (3) comparisons with auxiliary procedures of basically different derivations. The value of the method suggested increases in the unusual or abnormal year and tends to eliminate the possibility or reduce that magnitude of the 'big bust'.In discussion Mr. Harry I. Hunter cautions against using only procedure or independent variable for developing a water supply forecasting formula, and states that combination of variables may produces a more accurate and a better balanced forecast.
Keywords: Water supply forecasting