Radar measurements of snow avalanche full scale experiment in Ryggfonn.

Abstract

At the full scale experiment site of NG! in Ryggfonn, avalanche velocities and forces have been measured through 15 years. In April 1997 an Austrian developed INW pulsed Doppler radar was used to measure avalanche velocities simultaneously at 15 segments in the avalanche track. Each of the 15 segments had a length of 50 m, with a total length of the radar measurements of 700 m. Avalanche velocities of the flowing part were recorded for about 4 minutes in each segment. The recordings show the distribution of the avalanche velocity with time, simultaneously in each segment. In addition to the radar measurements, avalanche forces were recorded continuously at two locations in the track. The recordings show interesting results concerning the internal distribution of velocities in snow avalanches in relation to measurements of avalanche forces.