Using spatial and spatial-extreme statistics to characterize snow avalanche cycles

In December 2008, an intense avalanche cycle occurred in the eastern part of the southern French Alps. Using this case study, this paper illustrates how spatial statistics can be used to analyse such abnormal temporal clusters of snow avalanches. Spatial regression methods are used to quantify aggregation and gradients and highlight the three day snowfall as the main explanatory factor. A max-stable model is developed to evaluate the snowfall return period, so as to compare the studied cycle with previous ones and with empirical return periods for avalanche counts.