Statistical avalanche run-out modelling using GIS on selected slopes of Western Tatras National park, Slovakia

ABSTRACT: Without doubt avalanche run-out distances play a key role in landuse planning within avalanche prone areas. The Žiarska valley in Western Tatras is considered as one of the most ava-lanche prone valleys in the whole area of Carpathian Mountains. This environment represents a per-fect opportunity for studying and modelling extreme avalanche run-outs. The valley is frequently vis-ited by backcountry skiers as well as roads and several cabins are located there. Therefore a careful land use planning with respect to extreme avalanche run-out is crucial. First of all avalanche release zones were estimated by using an existing model proposed by Hreško. This model was changed and calibrated using avalanche data extracted from a database which is maintained by Slovak Centre for Avalanche Mitigation. The alpha-beta regression model developed in Norway has been used for esti-mating avalanche run-outs. This model is calibrated for use in Western Tatras. Topographical parame-ters from well known extreme avalanche paths have been collected using GPS. Data processing and model calibration have been elaborated in GIS environment. Avenue script for ArcView was written to perform automated run-out estimation based on alpha-beta regression model. Model managed fairly well to estimate runouts on some slopes while it failed to model runups. Finally the results were visu-alized by creating the fly-through simulations and 3D views. Winter season 08/09 with catastrophic avalanches showed the importance of avalanche run-out modelling. Many installations have been damaged due to improper land use planning without respect to extreme avalanches. Comparison be-tween model calculation and avalanche cadastre showed correlation