Abstract : 3K.10
Use of multicriteria analysis for delimitation of avalanche unleashing areas in Aguas Limpias Valley, Spanish Pyrenees

María Palomo, Javier Chueca, Asunción Julián
Instituto Nacional de Meteorología, Ministerio de Medio Ambiente

Avalanches are a serious risk in mountain areas, especially in avalanche prone locations, where people or objects can be affected by them. Having knowledge of the mechanisms and factors playing a part in their unleashing is fundamental towards an efficient land planning and management.

This work presents an avalanche triggering prone areas cartography in the headwaters of Aguas Limpias River (Upper Tena Valley, Spanish Pyrenees), where avalanches of various magnitudes have been registered, being that of winter 1996, affecting seriously the Respomuso Mountain Refuge, the most catastrophic one. In order to prepare this map, an extensive analysis of the terrain-related parameters was made (from Digital Elevation Model, aerial photography and field work information), integrated later in a Geographic Information System through eight variables: height, slope, orientation, slope morphology, surface cover, 0º C isotherm, snow accumulation areas and solar radiation. It was also considered the time evolution of the three latter variables along the snow season (December to May), in order to define significant spatial differences in avalanche triggering. We have delimited avalanche prone areas by using multicriteria analysis through the cartographic overlap of the different criteria used for the territory classification.