Item: GLIDE-SNOW AVALANCHES: THE INFLUENCE OF SPATIAL VARIATION IN INTERFACIAL FRICTION AND SNOW COVER ON AVALANCHE RELEASE
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Title: GLIDE-SNOW AVALANCHES: THE INFLUENCE OF SPATIAL VARIATION IN INTERFACIAL FRICTION AND SNOW COVER ON AVALANCHE RELEASE
Proceedings: International Snow Science Workshop Proceedings 2023, Bend, Oregon
Authors:
- Amelie Fees [ WSL Institute for Snow and Avalanche Research SLF, Davos, Switzerland ]
- Peter Lehmann [ Physics of Soils and Terrestrial Ecosystems, ETH Zürich, Switzerland ]
- Michael Lombardo [ WSL Institute for Snow and Avalanche Research SLF, Davos, Switzerland ]
- Alec van Herwijnen [ WSL Institute for Snow and Avalanche Research SLF, Davos, Switzerland ]
- Jürg Schweizer [ WSL Institute for Snow and Avalanche Research SLF, Davos, Switzerland ]
Date: 2023-10-08
Abstract: Glide-snow avalanches typically release in well-known avalanche paths due to a loss of friction at the ground-snow interface which is related to the presence of liquid water. However, the spatial distribution of liquid water and its influence on mechanical snow properties and the progression of local failures is unknown. As a result, predicting glide-snow avalanches and their release area remains difficult. We therefore built a model that captures mechanical snow interactions and investigated the impact of spatial variations in liquid water content (expressed as loss in interfacial friction) on glide-snow avalanche release probability and release area. In this threshold-based mechanical model, the snow cover is represented with hexagonal columns. The columns interact through compressive, shear and tensile bonds. Interfacial friction between the ground and the snow cover was implemented as a proxy for the liquid water content. The results suggest that our modeling framework can emulate the power-law release-area distribution of glide-snow avalanches as observed in 14 years of georeferenced time-lapse photographs at our field site. A sensitivity analysis showed that the homogeneity of the basal friction was the main influence on avalanche release area and the power law exponent while the spatial variation in snow cover properties was of second order influence. In the future, the implementation of additional model parameters such as snow loading, and local topography will improve our understanding of release probability and release-area size. This knowledge will help to assess crititcal conditions for large glide-snow avalanches and improve forecasting capabilities.
Object ID: ISSW2023_O9.05.pdf
Language of Article: English
Presenter(s): Amelie Fees
Keywords: glide-snow avalanche, power law distribution, statistical modelling
Page Number(s): 1047 - 1051
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