An Assessment of Run-Out Models Applied to Norwegian Snow Avalanches (original) (raw)

2016, International Snow Science Workshop 2016 Proceedings, Breckenridge, CO, USA

The aim of the present project was to evaluate four different models by using objective criteria and constant parameters, and to consider the models' applicability to Norwegian avalanches. RAMMS, Elba+, the Alpha-Beta model and the Energy Line model are the assessed models. The models are applied to 15 well-documented Norwegian avalanches with return periods from 100 to 300 years. RAMMS and Elba+ represent numerical dynamical models, whereas the Alpha-Beta model and the Energy Line model are empirical models based on topographic parameters. A main concern of the project was to compare the accuracy of the numerical and empirical models in terms of run-out distance, maximum velocity and velocity distribution in the run-out zone. The results showed that the two numerical models, RAMMS and Elba+, consistently modelled shorter run-out distances than recorded ones, but they had the best correlation coefficients in the statistical analysis. On the other hand, the two topographic models, developed for Norwegian conditions, had the least deviation in average run-out distance. All the models calculate maximum velocities within a realistic range. However, RAMMS and Elba+ probably calculate too small velocity gradients in the run-out zone compared to recordings from full-scale experiments. The Energy Line model, however, provided values that are more realistic. An accurately estimated distribution is extremely important when dimensioning avalanche protection measures. The statistical analysis shows that RAMMS and the Energy Line model overall provide the best results.