Item: Verification of high-resolution numerical weather models with regard to avalanche forecasting
Title: Verification of high-resolution numerical weather models with regard to avalanche forecasting
Proceedings: Proceedings of the 2000 International Snow Science Workshop, October 1-6, Big Sky, Montana
Authors: Claudia Roeger, David McClung, Roland Stull, Josh Hacker, Henryk Modzelewski, University of British Columbia, Vancouver, BC, Canada
Abstract: Meteorological factors are of major importance in avalanche forecasting. For regional (office-based) avalanche hazard evaluation, high-quality meteorological information is needed. Especially for computer-assisted forecasts (1 - 2 days into the future), highly accurate weather predictions are desired. The objective of this research is to determine whether output from high-resolution numerical weather prediction (NWP) models can be used as input for avalanche forecasting models. Two highresolution, real-time, numerical weather forecast models that are currently running at UBC are verified. The models use grid spacing of 3.3 km for the Whistler/Blackcomb ski area in the British Columbia Coast Mountains, and 2 km for Kootenay Pass in the Columbia Mountains. Standard statistical methods are used to compare the forecasts with surface observations of manual and automatic weather stations. The results look very promising. For example, for precipitation rate, wind direction and temperature, the MC2 2 km grid gives better results than the 10 km grid because the topography is captured more accurately. At Kootenay Pass, the NMS model produces comparable results for precipitation rate even though the resolution is lower. For temperature, an error reduction as much as 50 % was achieved using the postprocessing Kalman-predictor correction method. With such small errors (around 0.7 K), it looks quite promising that the forecast can be used for avalanche forecast models such as at Kootenay Pass where air temperature is a primary variable for wet avalanche prediction.
Keywords: avalanche forecasting, high-resolution numerical weather prediction, weather forecast verification
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