Snow avalanche research programme SIP-6. Ryggfonn. Full scale avalanche test site and the effect of the catching dam

Abstract

The effect of the 16 m high retaining dam in Ryggfonn has been analysed by using data from 12 dry snow avalanches. Except for one avalanche, which was stopped by the dam, all of these avalanches overtopped it and ran beyond the dam. Avalanche speeds were inferred from the arrival times at sensors 320 m and 230 m upstream of the dam. Based on these observations, the avalanche speed at the site of the dam and the run-out were simulated with the NIS model and compared to the observed run-out. The run-out of the observed avalanches is closely correlated to the avalanche velocity. The volume of the avalanches has a weaker correlation with the run-out.