Item: Spatial variability of snow stability on small slopes
Title: Spatial variability of snow stability on small slopes
Proceedings: 2002 International Snow Science Workshop, Penticton, British Columbia
Authors: Kalle Kronholm, Iiirg Schweizer and Martin Schneebeli, Swiss Federal Institute for Snow and Avalanche Research SLF, Davos, Switzerland
Abstract: Spatial snowpack variability is thought to strongly influence the fracture initiation and fracture propagation properties of the snowpack, thereby largely controlling the avalanche formation process. To investigate variations in stability on the slope scale, stuffblock and rammrutsch stability tests were carried out in an array on eight small avalanche slopes above timberline near Davos, Switzerland over the winter 2001-02. On each slope 17 tc 26 stability tests were done. The analysis focuses on failures in two persistent weak layers that were found on all eight slopes. The median and the spread of the stability values are calculated. Slopes with low average stability and low variation in stability are more critical than if either average stability or variation in stability is high. Slope scale trends in stability were found on some slopes. Depth of the failure layer partly explained variations in stability. The quartile coefficient of variation was of the order 50% for the drop heights and 20% if the slope scale linear trend was removed.
Keywords: snow stability, snow stratigraphy, stability tests, avalanche formation, spatial variability
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