Snow avalanche hazard prediction for Longyear valley, based on avalanche run-out models and taking in account the prognoses for climate change

Longyearbyen, the center for the main economic activities of Svalbard was partly developed on the slopes of Gruvefjellet and Platafjellet. A concern has been raised regarding the threat induced by avalanche runouts that could reach some of the building in the city. In this study the avalanche danger around Longyearbyen Barnehage, Lia and Nybyen is assessed using the Rapid Mass MovementS (RAMMS) dynamic 2D runout model developed by the WSL Institute for Snow and Avalanche Research (SLF) and the Swiss Federal Institute for Forest, Snow and Landscape Research (WSL). Results are compared with the conclusions of Norwegian Geotechnical Institute reports. The Arctic region being highly sensible to climate change the induced precipitation and temperature variations in the next century, and the induced snow density and cohesion increase were taken into account in a scenario following a 25% solid precipitation increase and a 10 C temperature increase. Runout distances seem to be little affected by the followed scenario. An attempt at reconstructing a slush flow event that occurred on January 20th 2012 was made.