Item: Risk and avalanche rescue
Title: Risk and avalanche rescue
Proceedings: Proceedings Whistler 2008 International Snow Science Workshop September 21-27, 2008
Authors: Krister Kristensen, Manuel Genswein, Dale Atkins.
Abstract: More than 6.7 % of the Norwegian land area features terrain steeper than 30 degrees. It is commonly assumed that these areas can be the source for both avalanches and rock fall. The building code in Norway states that new residential houses must not be built where the annual probability of avalanches exceeds 1/1000. During the last 20 years most of the exposed areas in the country were mapped with regards to the potential hazard. The maps show three zones of potential hazard with annual probability > 1/1000, not hazardous and not mapped. These maps cover ca. 80% of all areas that are exposed to hazards. In this analysis the maps were used together with the register of residents and houses to quantify the number of houses in and close to the hazardous areas. It was then assumed an average value per house to produce the total number of values at risk. Human lives and other values in the hazard zones were not included in this analysis. The results show that a considerable number of houses are exposed and that a slight change in the hazard zone extent will lead to a significant change in the number of exposed buildings. With regard to a potential climate change, this is an important issue for the evaluation of the societies future vulnerability. The risk to rescuers is of serious concern for the International Commission for Alpine Rescue (ICAR). For good reason, since ICAR receives annually reports of fellow rescuers injured or killed while on missions. In avalanche rescue many call outs occur when the general danger rating is 3 or high-er and where conditions are further deteriorating. This means that both the approach and the accident site can be exposed to avalanche danger. Under these circumstances the risk of rescue missions in avalanche terrain can be comparable to settings where explosions, structure collapses, hazardous materials, etc., present a risk to the rescue personnel. This work outlines a decision analysis approach to risk and benefit assessments in avalanche rescue missions. A simulation-optimization model allows for assessing the expected outcomes of rescue missions by considering key variables affecting both rescuers and the buried subject. The large number of input variables, their probability and the interaction between the input variables lead to a level of complexity which is difficult to handle without a well-structured decision making tool.
Presenters: Krister Kristensen.
Keywords: risk assessment, risk management, rescue simulation, rescuer safety, acceptable risk