A MIXED FLOWING/POWDER SNOW AVALANCHE MODEL

pie, Voellmy-type models are judged too. curately represent the complex flow beha. snow avalanches. They are, however, well Ii titioners. The depth-averaged turbidity siders entrainment and deposition proc not been applied to model more than one snow avalanche event (Fukushima & Parker three-dimensional models have not yet been. flowing avalanche models. In addition, they computationally demanding and expensive. tioners have the know-how, the money or infrastructure to apply them to real situ. Despite these modelling attempts, greatest hindrance to the development of a ing/powder snow avalanche model is the perimental data. The Swiss Valle de la Sion was constructed to remedy this problem ( per in these proceedings). For an exainpleof avalanche in this experimental area, see Fi though the test site was partially destroyed catastrophic avalanche winter of 1999, e was gathered, especially photogrammetric ance measurements and video recordings. development of a more complicated avala ics model. Work is presently underway to test site. In the following, a mixed flowing/powder model is presented. The motion of the powder cloud is d set of depth-integrated balance equatio~s mass and momentum. The incompressible, powder cloud is assumed to be composed des suspended in air to form a continuOU