Application of statistical and hydraulic-continuum dense-snow avalanche models to five real European sites

We test the behaviour of two statistical avalanche models and three hydraul ic-continuum models of varying dimensionality against five reference events . For the hydraulic models, reference friction coefficients are produced th at replicate the runout distance of the historical event. The model sensiti vity to friction coefficients, release depth, release area and runout dista nce is also analysed. The hydraulic-continuum models yield similar reference coefficients on the simplest topography, but diverge for more complex paths, highlighting the i mportance of boundary conditions on model performance. The Coulomb friction (mu) shows a closer relation to runout distance than the turbulent frictio n (xi). For models of this type, the debris deposition pattern is useful fo r selecting model coefficients, rather than relying purely on runout distan ces. The results of the sensitivity analysis are site-specific, again highlighti ng the importance of terrain as a model boundary condition. The release are a seems ro have less of an influence on model results than the fracture hei ght and xi. In general, the models are most sensitive to mu. At the end of the paper, we propose a scheme for avalanche hazard zoning that integrates the statistical and dynamic models, such that zoning can be undertaken with some confidence in model output. (C) 2000 Elsevier Science B.V. All rights reserved.