This report reviews the second year of work on the Washington State Highway Commission Department of Highways project Central Avalanche Hazard Forecasting (WSDH Agreement Y-1700) to test the feasibility and effectiveness of central avalanche forecasting for the Cascade Mountain passes and adjacent area. The possibilities and techniques for improving both mountain weather and related avalanche forecasts for use by WSDH during winter operation in the mountain passes were further explored, and, secondarily, the usefulness of an area-wide forecasting service to other cooperating agencies. This report defines the significant changes from the first year of operation in collection, assimilation or transmission of snow, weather and avalanche data by the Forecasting Office, and details modifications of the data network itself, especially new instrumentation and telemetry equipment. Weather and avalanche forecasting accuracy and reliability are assessed by comparing daily weather and avalanche forecasts with field data. The conceptual framework and analytical methods used by forecasters to deduce current and probable future avalanche activity from the available data network input and current and extrapolated meteorological data are presented. A general preliminary guide to forecasting methodology for the Washington Cascades is defined and discussed.
University of Washington. Dept. of Atmospheric Sciences.
Avalanches, Data collection, Hazards, Instrumentation, Measures of effectiveness, Mountains, Passes (Mountains),
Roadside hazards, Reliability, Snow, Telemetry, Weather forecasting.