A proposal for avalanche susceptibility mapping in the Pyrenees using GIS: the Formigal-Peyreget area (Sheet 145-I; scale 1:25.000)

Abstract

The aim of this work is to show a proposal for avalanche susceptibility mapping (scale 1:25.000) using Geographic Information Systems (GIS). The map to which the article accompanies (Formigal; Sheet 145-I) follows strictly the dimensions of the Spanish Topographic Cartography series at scale 1:25.000. The Formigal-Peyreget area, located in the Central Spanish and French Pyrenees, is one of the Pyrenean regions where avalanche risk is more noticeable. The methodology involves the use of GIS to model avalanche starting zones, including the multi-criteria cateogorisation of four variables: (i) minimum altitude of the regional isotherm of 0°C for the winter months; (ii) slope; (iii) ground cover; (iv) morphology of the slope (curvature). The information presented in the map classifies avalanche start zones susceptibility into four categories: low, moderate, high and very high. This methodology is intended to be used as a reference for the production of future maps of avalanche susceptibility in other regions where the method is deemed appropriate.