Practical experience with the Austrian powder avalanche simulation model in hazard zoning : 25 [tewnty five] Years of Snow Avalanche Research

Oslo

1998

S. 229-233

3 Abb., 4 Lit. Ang.

Bandaufführung

59418

In some cases the classical avalanche runout models cannot be used for the delimitation of avalnache hazard zones. Especially, if not only the straight runoff distance is to be determined but a lateral outbreak caused, for example, by a curve in the avalanche path is to be expected. In this case the powder avalanche model shows the behavior of the powder part of the drysnow avalanche. The present paper shows the results of the investigation of three avalanches in the district Reutte in the Tyrol. In case of the Wiestal-avalanche in teh community of Bichlbach it was not clear whether the avalanche is able to cross over a natural deflecting ridge and endanger some houses which are situated behind this ridge. The avalanche simulation confirms vague historical reports about a destroyed church on the ridge. In the community of Häselgehr two hamlets have been situated close to a mountainside for several hundred years and it was not clear whether the terrain ridge situated above the houses is high enough to deflect big dry-snow avalanches with a high powder component. The use of the powder avalanche model shows why the houses could survive for such a long time without damages. In the mentioned three cases, it would not be possible to delimitate the hazard zones on the basis of commonly used avalanche models.