Assessment and mapping of snow avalanche risk on the walking track to access to Vega de Urriellu, Picos de Europa (NW of Spain)

Abstract

The growing interest in natural mountain areas related to winter recreation activities requires the elaboration of studies which quantify the risk of avalanches. In this work the main goal has been to assess the avalanche hazard and associate risk from an Avalanche Hazard Index (AHI) in one of the most popular mountain routes in Picos de Europa, the access walking track to Vega de Urriellu from Collado Pandébano, the PR-PNPE 21. Firstly, it has been necessary to locate and identify the avalanche path crossing the mountain route using different information: morphological, vegetation and historical. The frequency of the avalanches was estimated from the comparison of temporal sequences of aerial photographs, field observations, survey population and average slope of avalanche path. As regards to the risk assessment, several possible scenarios in relation to the variability of the data have been considered. The AHI obtained by this procedure is generally low for the entire winter season, moderate in certain situations when the factor exposure is high, and finally this Index is high at Easter due to the special visitors traffic. Also, information to the user is proposed as a means of mitigating risk.