Experiences in Avalanche Assessment With the Powder Snow Avalanche Model Samosat

In 2004 the Forest Technical Service for Avalanche and Torrent Control (WLV) has initi- ated the development of the new powder snow avalanche model SamosAT. The program SamosAT provides simulation tools for dense and powder snow avalanches. The previous Samos simulation platform has been reworked in order to obtain improved simulation results, new calculation methods and enhanced software handling. Major changes have been made in the dense flow friction model, in the alteration of the simulation environment of the powder part with enhancements in the 3D suspen- sion mesh and finally in optimising the resuspension layer, which is responsible for the transition of the dense snow into the powder layer. The calibration of the model was done with 22 well documented reference avalanches. The model was released in the end of 2007 and officially implemented in the daily work of avalanche danger assessment and hazard mapping. In the last years numerous simula- tions have been done with the model including recalculations of actual avalanche events from 2009. This paper gives information about the experiences with the avalanche model SamosAT. On the basis of several case studies the improvements as well as the limits of the new program are explained.