The avalanche risk report for Longyearbyen is now available. After the deadly avalanche on December 19, 2015 and the precautionary evacuations in early November 2016, the report has been awaited with eagerness. It was compiled by NVE (Norges vassdrags- og energidirektorat, Norwegian directorate for waters and energy within the ministry for oil and energy) and it is based on maps and aerial photography, terrain modeling, climate analysis, historical experience, on-site investigations and computer modeling.
For the public, the results are more relevant than the methodical background. The report includes a map that shows endangered areas in three colours. The areas where damage caused by avalanches happens with a likelihood of 1:5000 per year is marked in yellow. In other words: damage caused by an avalanche has to be expected every 5000 years – statistically, that is.
Areas marked orange have an annual risk of 1:000 or avalanche damage every 1000 years. And then there are the red areas, where an avalanche has to be expected once per century. The risk of a devastating event is one per cent every year.
This risk assessment includes snow and slush avalanches, mudslides and rockfalls. Some parts of Longyearbyen are “only” exposed to particular hazards within this list. This can mean that different areas may be exposed to danger at different seasons or in different weather situations.
A first look at the avalanche risk map makes the viewer take a breath. No less than 154 flats as well as two guest houses are inside the red zone. These addresses are faced with an annual risk of 1:100 of a potentially catastrophic event, causing great damage and putting life at risk.
The obvious question is how Longyearbyen will deal with this situation. it is clear that the option to move all the houses concerned quickly to safe areas is not available. That will neither technically nor politically and financially be possible, and there is the issue of space being available in sufficient quantities in Longyearbyen (remember, it is a valley, and there are rivers, slopes and a fjord not far from wherever you are). As a result, the houses will remain wherever they are at least for quite a while.
Longyearbyen will obviously be developed in areas that are not endangered, making sure as much housing as possible will be available in these areas in the future. Securing dangerous slopes with technical will also be discussed.
For the time being, there is no other option but keeping the avalanche warning system upright and evacuate endangered addresses in risk situations.
It was emphasized that there is a number of communities in Norway who are in similar situations. In the end, it is normality in a mountain and winter country such as Norway, and communities will naturally have to deal with that. This has recently been ignored in Longyearbyen. A high price was paid in December 2015.
It can be taken for granted that politicians from the local administration (Lokalstyre) in Longyearbyen to relevant departments in Oslo have got some homework to do. Meanwhile, inhabitants of many houses in Longyearbyen will have to live with temporary evacuations on a short warning during avalanche risk weather.
Avalanche risk map for Longyearbyen (NVE).
Direct link to the avalanche report and direct link to the avalanche risk map.
Sources: Sysselmannen, Svalbardposten