Cartography of probable avalanche starting zones in the Alto Gállego Valley (Spanish Central Pyrenees) using Geographical Information System

Abstract

We present in this work the cartography of probable avalanche starting zones in the Alto Gállego valley (Spanish central Pyrenees) made by using a Geographical Information System (ArcGIS). The conditioning factors used to generate the general model for probable avalanche starting zones (MGZPSA) were: altitude of the monthly regional 0ºC isotherm (December-April), slope and surface cover. The additional incorporation of the monthly solar radiation variable allowed to classify these areas into three susceptibility sectors according to the radiation inputs and their subsequent contribution to the instability of the snowpack (solar radiation model; MRSZPSA). The two models were validated using two control areas with contrasted aspect located in the high sector of the valley.