Vulnerability of houses and persons under avalanche impact – the avalanche at Longyearbyen on 2015-12-19

Abstract

This study uses data from the avalanche that killed two persons and destroyed eleven essentially identical wood-frame houses in Longyearbyen, Svalbard, on 2015-12-19. The avalanche is back-calculated with a dynamical model to estimate the spatial pressure distribution. For each affected building, the structural damage is categorized according to the remaining degree of protective function. However, relating the damage to the impact pressure is complicated by unusual features of this event. Finally, the fraction of inhabitants of each building who were injured or killed is related to the degree of structural damage instead of the usually used indicators pressure or velocity. In this way, it will be possible to compare and combine data from different building types and events to improve the estimate of the vulnerability of persons inside buildings against snow avalanches. Such vulnerability functions are needed for quantitative avalanche risk analysis in the context of planning mitigation measures or for legislative purposes. The data from this one event is not sufficient for establishing these functions, but the study will be extended to other events on which sufficiently detailed information is available.