Avalanche simulation with SAMOS

Abstract

Dry snow avalanches consist of two distinct layers. A dense-flow layer is superposed by a powder-snow layer, a cloud of relatively small ice particles suspended in air. The density of this suspension is one order of magnitude smaller than that of the dense flow. A simulation model for dry avalanches has been developed, based on separate sub-models for the two layers. The sub-models are coupled by an additional transition model, describing the exchange of mass and momentum between the layers. The fundamentals of the two-dimensional granular flow model for the dense flow and of the three-dimensional turbulent mixture model for the powder flow are presented. Results of the complete coupled model, SAMOS (Snow Avalanche MOdelling and Simulation), applied to observed catastrophic avalanche events, are discussed, and the prediction of powder-snow pressures acting on a tunnel bridge is briefly described. SAMOS is used routinely for hazard zoning at the Austrian Federal Service for Torrent and Avalanche Control. © International Glaciological Society.