modeling the influence of snow cover temperature and water content on wet-snow avalanche runout
;C. Vera Valero;N. Wever;M. Christen;P. Bartelt
anziam journal2018Vol. 18pp. 869-887
169
valero2018naturalmodeling
Abstract
Snow avalanche motion is strongly dependent on the temperature and water
content of the snow cover. In this paper we use a snow cover model, driven by
measured meteorological data, to set the initial and boundary conditions for
wet-snow avalanche calculations. The snow cover model provides estimates of
snow height, density, temperature and liquid water content. This information
is used to prescribe fracture heights and erosion heights for an avalanche
dynamics model. We compare simulated runout distances with observed avalanche
deposition fields using a contingency table analysis. Our analysis of the
simulations reveals a large variability in predicted runout for tracks with
flat terraces and gradual slope transitions to the runout zone. Reliable
estimates of avalanche mass (height and density) in the release and erosion
zones are identified to be more important than an exact specification of
temperature and water content. For wet-snow avalanches, this implies that the
layers where meltwater accumulates in the release zone must be identified
accurately as this defines the height of the fracture slab and therefore the
release mass. Advanced thermomechanical models appear to be better suited to
simulate wet-snow avalanche inundation areas than existing
guideline procedures if and only if accurate snow cover information is
available.