Determining avalanche modelling input parameters using terrestrial laser scanning technology
Résumé
In dynamic avalanche modelling, data about the volumes and areas of the snow released, mobilized and deposited are key input parameters, as well as the fracture height. The fracture height can sometimes be measured in the field, but it is often difficult to access the starting zone due to difficult or dangerous terrain and avalanche hazards. More complex is determining the areas and volumes of snow involved in an avalanche. Such calculations require high-resolution spatial snow surface data from before and after the avalanche. In snow and avalanche research, terrestrial laser scanners are used increasingly to accurately map snow depths over an area of several km². We present data from a terrestrial laser scan campaign of an artificially triggered avalanche at the Col du Lautaret test site (2058 m) in the French Alps and provide data for the validation of dynamic avalanche models. Two terrestrial laser scans from before and after the avalanche release provide the snow surface data required for our analysis. The scans are accurately referenced with surveyed control points and multistation adjustment, and the resulting data analyzed in GIS. We show the areas and volumes of a) snow released in the starting zones, b) entrained in the track, and c) of the avalanche deposit. Furthermore, we present results for the fracture height, path length, and the track width of the avalanche. Additional measurements from a total station and of snow densities provide the data for comparison and validation of the TLS data. Our results show the ability of TLS to determine avalanche modelling input parameters efficiently and accurately.
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