VALANCA. A cellular automata model for simulating snow avalanches

Numerical modelling is a major challenge in the prevention of hazards related to the occurrence of catastrophic phenomena. Cellular Automata methods were developed for modelling large scale (extended for kilometres) dangerous surface flows of different nature such as lava flows, pyroclastic flows, debris flows, rock avalanches, etc. This paper presents VALANCA, a first version of a Cellular Automata model, developed for the simulations of dense snow avalanches. VALANCA is largely based on the most advanced models developed for flow-like landslides, and adopts some innovations such as outflows characterized by the position of mass centre and explicit velocity. First simulations of welldocumented snow avalanches occurred in the Davos region, Switzerland (i.e. the 2006 Rüchitobel and the 2006 Gotschnawang snow avalanches) show a satisfying agreement concerning the avalanche path, snow cover erosion depth, deposit thickness and areal distribution. Furthermore, preliminary simulations of the Gotschnawang snow-avalanche, by considering the presence of mitigation structures, were performed.