Optimization and probabilistic calibration of avalanche block models

The Norwegian Geotechnical Institute (NGI) has been performing full-scale avalanche tests at Ryggfonn in western Norway for more than 30 years. During those years, measurements from about three dozen dry-snow avalanches have provided information on front velocities and runout distances. Some of those measurements were used to evaluate "optimal parameters" for a simple avalanche model and to calibrate the model, following a well-defined probabilistic method. Traditionally, parameters of those kinds of models were evaluated from runout analysis disregarding any dynamics. The set of roughly 20 observed avalanches from one single path including, estimations of the front velocities at three points in the lower third of the track provide a unique opportunity for introducing uncertainty quantification methods for evaluating the performance of similar kinds of mass block models. We present the optimization, the model calibration and results from the model performance testing. (C) 2009 Elsevier B.V. All rights reserved.