Relative influence of mechanical and meteorological factors on avalanche release depth distributions: An application to French Alps

The evaluation of avalanche release depth distributions represents a major challenge for hazard management. This paper presents a rigorous formalism in which these distributions are expressed through a coupling of mechanical and meteorological factors. Considering that an avalanche can occur only if the snowfall depth exceeds a critical value corresponding to a stability criterion, release depth distributions obtained from a slab-weak layer mechanical model are coupled with the distribution of 3-day extreme snowfalls. We show that this coupled model is able to reproduce field data from 369 natural slab avalanches in La Plagne (France). Not only the power-law tail of the distribution, corresponding to large slab depths, but also the core of the distribution for shallow slab depths, are well represented. Small to medium-sized avalanches appear to be controlled mainly by mechanics, whereas large avalanches and the associated power-law exponent, are influenced by a strong mechanical-meteorological coupling. Finally, we demonstrate that the obtained distribution is strongly space-dependent, and, using a consistent interpolation formalism, our model is used to obtain release depth maps for given return periods. Citation: Gaume, J., G. Chambon, N. Eckert, and M. Naaim (2012), Relative influence of mechanical and meteorological factors on avalanche release depth distributions: An application to French Alps, Geophys. Res. Lett., 39, L12401, doi:10.1029/2012GL051917.


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Geophysical Research Letters, 39, 12, n/a-n/a
Year:
Jun 20 2012
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