Considerations on the Glide Snow Avalanches based on the Stauchwall Model

Avalanches are natural events that can have consequences such as silvicultural losses, infrastructural damages, fatalities. In this paper, the attention is given to glide avalanches starting by a glide crack, a tensile crack that propagates at the crown – the upper release limit – due to the internal stress variation. However, the presence of a glide crack does not always give rise to a glide avalanche. In fact, when the slab starts to move, interacts with the stauchwall (the downslope boundary of the slab) which can fail or withstand.The Stauchwall model was adopted in order to verify if the gliding avalanche is triggered or not, by analyzing the dynamic stability of a slab subjected to an initial perturbation. In this paper, the model has been expanded by coupling it with a stress failure criterion. Thanks to this new failure criterion, it is possible to investigate the possible causes of subsequent glide avalanches triggering (in terms of hours or even days) after the crack propagation. In addition, the effect of a skier’s fall/brake on the slab stability is analyzed. Finally, a sensitivity analysis of the model pointed out the important role played by the basal snow/soil friction. Therefore, it is shown that actions meant to increase this characteristic may be taken into account to effectively prevent glide avalanches