On probabilities of avalanches triggered by alpine skiers. An application of models for counts with extra zeros

摘要

In Austria most fatal snow avalanche accidents are caused by skiers or snowboarders. For example in winter 2001/02 79 avalanche accidents (17 fatalities) are reported. 16 from 17 fatalities were caused by alpine skiers or snowboarders. By far the highest number of accidents took place in Tyrol (2001/02: 47 accidents/ 12 fatalities). However it is rather difficult to predict the risk (=probability) of avalanche events on a backcountry ski slope under given conditions. About 10 years ago the mountain guide Werner Munter (1997) suggested a quantitative method to estimate the risk of avalanche events. Assumig that variates 1. danger levels from the local avalanche information service (l=low to 5=very high) 2. incline of the slope (3 classes from flat to steep) 3. aspect of the slope (north, south) and 4 skiers behaviour.