Item: Climate factors associated with major avalanche events on the wasatch plateau, utah
Title: Climate factors associated with major avalanche events on the wasatch plateau, utah
Proceedings: 2002 International Snow Science Workshop, Penticton, British Columbia
Authors: Elizabeth G. Hebertson, USDA Forest Service, Forest Health Protection, Odgen Field Office, Ogden, Utah, Michael J. Jenkins, Utah State University, Logan, Utah
Abstract: Dendro-ecological methods were used to construct avalanche chronologies for 16 paths on the Wasatch Plateau, Utah. Major avalanche years between 1928-1996 were distinguished from others using weighted avalanche and path indices. Since the 1900's, avalanche chronologies and historic documents indicate that large widespread avalanches events occurred during winters of 1932, 1936, 1938, 1944, 1952, 1957, 1965, 1974, 1977, 1978, 1983,1986, 1989 and 1992. A binary classification tree analyses (CART) used climate data from the area to predict the occurrence of major avalanches during the period of study. The CART model provided a good probability for predicting non-avalanche, or minor years (0.67). The correct classification of major avalanches was only fair (0.53). The lack of high quality climate data and the absence of snow pack information may have prohibited obtaining a higher classification probability for major avalanches. The model, however, may help substantiate explanations of avalanche formation and initiation in the intermountain region, or serve to generate alternative hypotheses for predicting major avalanche events. Avalanche professionals and land managers might use this information to augment conventional strategies for protection, forecasting, land use planning and management. This information also has broad ecological implications increasing our understanding of major avalanches as important disturbances of intermountain alpine and subalpine ecosystems.
Keywords: snow avalanches, intermountain climate, tree-ring analyses, disturbance ecology
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