Item: Frequency/magnitude relationship of avalanches in the chugach range, alaska
Title: Frequency/magnitude relationship of avalanches in the chugach range, alaska
Proceedings: Proceedings of the 1996 International Snow Science Workshop, Banff, Canada
Authors: David Hamre and Doug McCarty, Avalanche Control, Alaska Railroad, Box 11-1492, Anchorage, AK 99511, phone: 907-344-8220, fax: 907-522-7672, Department of Earth Sciences, Montana State University, Bozeman, MT 59716, phone: 406-585-9222, fax: 406-994-6
Abstract: Since 1946, the Alaska Railroad has systematically recorded natural avalanche activity to the train track level. Parameters recorded include date, location, and apparent volume computed by length and width on the train track. This relatively long term record shows a significant relationship between frequency and magnitude on individual avalanche paths and the Chugach Range as a whole. For each avalanche path, the distance between Beta and Alpha angles are calculated and the train track position expressed as a percentage of Beta in order to normalize the runout distance expression. The % Beta term standardizes avalanche runouts so that a significant data set can compare frequency and magnitude for a large number of avalanche paths in a single area. A regression analysis defines the overall frequency relationship for all avalanche paths at any given location relative to the measured Beta angle. This information can be used in the design of fixed facilities in runout zones to determine the likely frequency of major avalanche events at any location. A more refined analysis of risk levels in these locations is thus possible.
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Keywords: frequency, magnitude, chugach, runout
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