Item: Proceedings of the 2004 international snow science workshop, jackson hole, wyoming
Title: Proceedings of the 2004 international snow science workshop, jackson hole, wyoming
Proceedings: Proceedings of the 2004 International Snow Science Workshop, Jackson Hole, Wyoming
Authors: Kalle Kronholm 1, * and Karl W. Birkeland 1, 2 1 Department of Earth Sciences, Montana State University, Bozeman MT, USA 2 U.S.D.A. Forest Service National Avalanche Center, Bozeman MT, USA
Abstract: This research uses a two-dimensional cellular automaton model, with inputs taken from field data, to mimic snow slab avalanche release. The initial weak layer shear strength in the model follows a normal distribution with known mean and standard deviation. For each realization of the spatial distribution of weak layer shear strength, the model stresses all cells equally until the weakest cell fractures. The stress from the fractured cell is transferred to cells in the neighborhood of the fractured cell, possibly causing a propagation of the fracture and a model avalanche. The stochastic shear strength field makes the model avalanche size stochastic for statistically constant initial conditions. The standard deviation of shear strength strongly affects the proportion of model avalanches covering nearly all cells in the model, with low variability leading to a high proportion of large model avalanches, a result that supports previous conceptual models. Stress transfer properties in the model are also important for the proportion of large model avalanches, but no field data exist to constrain these values. Spatial auto-correlation of shear strength is likely to be important for the size of model avalanches, and will be built into a future version of the model.
Keywords: stochastic, avalanche release, shear strength, shear stress, fracture propagation
Digital Abstract Not Available