International Snow Science Workshop Proceedings - Montana State University Library

Item: Analyzing the Atmosphere-Snow Energy Balance for Wet-Snow Avalanche Prediction

• • Title: Analyzing the Atmosphere-Snow Energy Balance for Wet-Snow Avalanche Prediction

    Proceedings: Proceedings, 2012 International Snow Science Workshop, Anchorage, Alaska

    Authors:

    • Christoph Mitterer  [ WSL Institute for Snow and Avalanche Research SLF, Davos, Switzerland ]
    • Jürg Schweizer  [ WSL Institute for Snow and Avalanche Research SLF, Davos, Switzerland ]

    Date: 2012

    Abstract: Melt water is the major driver of wet-snow instability. Its percolation and interaction with snow is complex, poorly understood and hence not well depicted in today’s snow cover models. As snow melt depends on the energy input into to the snow cover, we computed the energy balance and studied whether it is a good proxy for predicting periods with high wet-snow avalanche activity. The energy balance was calculated for virtual slopes at different elevations for the aspects south and north using the 1-D snow cover model SNOWPACK. In addition to the computed energy balance and its components, we used recorded meteorological variables to compare wet-snow avalanche days to non-avalanche days for four consecutive winter seasons in the surroundings of Davos, Switzerland. Air temperature, the net shortwave radiation and the energy input integrated over 3 or 5 days discriminated best between event and non-event days. Multivariate statistics, however, revealed that for better predicting avalanche days, information on the cold content of the snowpack (i.e. snow temperature) or the snow surface temperature is needed. This additional information indicates whether the energy input was used for warming the snowpack or directly for melting. Prediction accuracy with measured meteorological variables was as good as with computed energy balance parameters, but simulated energy balance variables accounted better for different aspects, slopes and elevations than meteorological data.

    Object ID: issw-2012-077-083.pdf

    Language of Article: English

    Presenter(s): Unknown

    Keywords: snow pack, wet snow avalanches, avalanche danger scale,

    Page Number(s): 77-83

    Subjects: wet snow snowpack conditions avalanche occurrence

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