Accute avalanche assistance Longyearbyen
Two avalanche experts from NGI arrived in Longyearbyen on Svalbard Saturday night, 19. December 2015, to assist the local authorities with the assessment of avalanche danger and the need for the evacuation from vulnerable areas. A large avalanche hit a residential area in Longyearbyen in the morning. Two people were killed.
Since the 1990 's NGI has been engaged by local authorities at Svalbard to evaluate the avalanche danger in Longyearbyen, and thereby have very good knowledge of the area which was struck by an avalanche in the morning of Saturday 19th December 2015. The avalanche occurred as a result of heavy snowfall in combination with very strong wind. A loose layer of coarse grained snow close the ground, which was formed earlier in the winter/late autumn, was the weak layer in the snow cover.
Additional fresh snow fall and strong winds appeared after the avalanche. The avalanche danger was therefore still considered as high. The avalanche experts assessed the avalanche danger on several areas around Longyearbyen and gave advice to the local authorities with respect to the evacuation of vulnerable buildings.
Pictures from the Avalanche in Longyearbyen 19th December 2015; The large picture on top shows the hoses wrecked by the avalanche. The Picture series above, from top left: Housing demolished by Avalanche, snow masses forced its way into the houses, a map With marked danger areas, from one of many public information meetings, HM The Queen of Norway visited the site in early January 2016, example of Avalanche alert statement.
Daily avalanche alerts for Longyearbyen
On behalf of the Governor of Svalbard, NVE gave NGI the task of preparing daily warning alerts of avalanche danger in Longyearbyen. NGI has long experience in preparing suchs daily alerts for various authorities and areas.
NGI got the call from NVE about this task Monday afternoon, 21. December. Already in the course of the same day NGI had established a solution for such avalanche alerts, which was operating from 23. December.
Information about local snow conditions in Longyearbyen is reported to NGI, and together with the assessment of the meteorological data and topographical conditions, this form the basis of the NGI daily alert reports of avalanche hazard and probability for an avalanche to reach housing and infrastructure. Avalanche alerts are sent every morning to NVE who forward them to the authorities at Svalbard. The avalanche danger is set according to the European Avalanche Hazard Scale.
The daily avalanche alert for Longyearbyen was during the winter of 2016 transferred to NVE, together with the other regional avalanche alerts from NVE.
Håkon Heyerdahl
Head of Section Slope Stability and Risk Assessment hakon.heyerdahl@ngi.no+47 951 25 767