Item: When do avalanches release: investigating time scales in avalanche formation
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Title: When do avalanches release: investigating time scales in avalanche formation
Proceedings: International Snow Science Workshop Proceedings 2018, Innsbruck, Austria
Authors:
- Alec van Herwijnen [ WSL Institute for Snow and Avalanche Research SLF, Davos, Switzerland ]
- Matthias Heck [ WSL Institute for Snow and Avalanche Research SLF, Davos, Switzerland ]
- Bettina Richter [ WSL Institute for Snow and Avalanche Research SLF, Davos, Switzerland ]
- Betty Sovilla [ WSL Institute for Snow and Avalanche Research SLF, Davos, Switzerland ]
- Frank Techel [ WSL Institute for Snow and Avalanche Research SLF, Davos, Switzerland ]
Date: 2018-10-07
Abstract: Forecasting snow avalanches requires a detailed understanding of the influence of meteorological boundary conditions on avalanche formation. For instance, while it is widely known that avalanche activity generally increases during snow storms, much less is known about typical time scales involved in avalanche formation. In other words, we generally do not know how quickly avalanche activity rises or when peak activity has been reached. Whereas meteorological data are nowadays readily available with high temporal resolution, the corresponding avalanche occurrence data are lacking. This is mainly because data on avalanche activity obtained through conventional visual observations are incomplete and inaccurate, especially regarding the release time. To identify characteristic time scales and dominant meteorological drivers associated with avalanche activity, we therefore used unique avalanche activity catalogues obtained through seismic and radar monitoring in combination with local meteorological measurements and snow cover simulations. Results show that different meteorological drivers related to avalanche activity throughout a season: energy input into the snow cover was a dominant driver late in the season, while modeled precipitation correlated best with avalanche activity earlier in the season. While these findings are not surprising, having more accurate release times for the avalanche events allowed us to cross-correlate meteorological drivers with avalanche activity to identify time scales. For precipitation, time scales were on the order of several days, while for energy input later in the season, time scales were on the order of several hours to one day. Finally, by using a moving windowed cross-correlation approach, we clearly identified regime changes throughout the season. Overall, our findings show that accurate avalanche activity data can provide novel insight into avalanche formation processes and ultimately can help improve avalanche forecasting using readily available meteorological data and snow cover simulations.
Language of Article: English
Presenters:
Keywords: Avalanche forecasting, remote avalanche detection, detrended cross-correlation, avalanche formation, meteorological drivers
Page Number(s): 1030-1034
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Digital Abstract Not Available
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