Sass O.,Institute For Geographie Und Raumforschung |
Heel M.,Universitatsstrasse 10 |
Hoinkis R.,Institute For Physische Geographie |
Wetzel K.-F.,Universitatsstrasse 10
Zeitschrift fur Geomorphologie | Year: 2010
Debris deposition by avalanches was monitored for six years at the Arnspitze south slope in the North-Tyrolean Limestone Alps. The slope investigated was deforested by a severe wildfire event in 1946 and is still largely vegetation-free today. We collected avalanchetransported debris on the snow fields at the base of the slope after ground avalanches in spring. The results show mean sediment yields of 1261 km-2 a-1; the mean erosion rate is 48 mm ka-1 for bedrock or 70 mm ka-1 for soil/debris, respectively. These values are much higher than most previous measurements reported in the literature. Avalanche erosion is extremely variable between the years, ranging from 01 to 215 t per year. The thickness of the snow cover, the timing of the spring melt, debris storage in the preceding years and unknown random factors appear to be responsible for the temporal variations. There are also large spatial differences between the sub-catchments. The highest absolute removal (in tonnes) occurs in the largest catchments; the correlation between catchment size and removal rate (tonnes per unit size) is positive but weak. The investigations indicate that process equilibrium remains disturbed, even after more than 60 years have elapsed. © 2010 Gebr. Borntraeaer Verlaasbuchhandluna. Stuttaart. Germany.