Item: Initial description of avalanche winter regimes for western canada
Title: Initial description of avalanche winter regimes for western canada
Proceedings: Proceedings of the 2004 International Snow Science Workshop, Jackson Hole, Wyoming
Authors: Pascal Hageli and David M. McClung, Atmospheric Science Program, The University of British Columbia, Vancouver B.C., Canada, Dept. Geography, The University of British Columbia, Vancouver B.C., Canada
Abstract: Existing snow climate classifications rely heavily on meteorological parameters that describe the average weather during the main winter months. Field experience and measurements, however, show that the character of snowpack weaknesses including their type structure and details of formation are the primary indicators of avalanches that form. Such characteristics are not a formal part of any snow climate classification scheme. Therefore, such classifications can only be of limited use for avalanche forecasting purposes. The focus of this study is the analysis of persistent snowpack weaknesses in Western Canada, an area with a wide range of weather and snow conditions. Observations from the industrial information exchange (InfoEx) of the Canadian Avalanche Association are used to examine the frequency, sequence and distribution of the most common snowpack weakness types and their related avalanche activity. The results show significant temporal and spatial variations, even in areas with the same snow climate characteristics. The transitional Columbia Mountains, for example, exhibit snowpack weakness characteristics that clearly go beyond a simple combination of maritime and continental influences. 'Avalanche winter regime' is suggested as a new term to describe and classify local snow and avalanche characteristics that are directly relevant for avalanche forecasting. Three distinct avalanche winter regimes are identified for Western Canada.
Keywords: snow climate, avalanche climate, avalanche winter regime, avalanche forecasting
Digital Abstract Not Available