Characteristics of wet-snow avalanche activity: 20 years of observations from a high alpine valley (Dischma,Switzerland) |
| |
Authors: | Stefano Baggi Jürg Schweizer |
| |
Institution: | (1) WSL Institute for Snow and Avalanche Research SLF, Flüelastrasse 11, 7260 Davos Dorf, Switzerland |
| |
Abstract: | The occurrence of wet-snow avalanches is, in general, poorly understood. For 20 years (winters of 1975–1976 to 1994–1995),
the avalanche activity has been observed in the Dischma valley near Davos (Eastern Swiss Alps). The study area comprises a
large starting zone of north-easterly aspect (2,300 m a.s.l.) with several avalanche paths. We have analyzed the occurrence
data in combination with meteorological and snowpack data collected at an elevation of 2,090 m a.s.l. During the 20-year observation
period, almost 800 wet-snow avalanches were observed, about 4.5 times more loose snow avalanches than slab avalanches. Considering
both types of avalanches jointly, snow depth, precipitation and air temperature showed the highest correlation with avalanche
activity. Most loose snow avalanches occurred when air temperature was high and/or after a precipitation period. Slab avalanches
occurrence was primarily related to warm air temperatures and snowpack properties such as the isothermal state and the existence
of capillary barriers. Radiation did not show up as a significant variable. The results suggest that in a transitional snow
climate wet-snow avalanches are, as dry snow avalanches, often related to precipitation events, and that wet slab instability
strongly depends on snowpack properties in relation to warming of the snowpack and melt water production. |
| |
Keywords: | Snow avalanche Wet snow Snow cover Avalanche forecasting |
本文献已被 SpringerLink 等数据库收录! |
|