Wet Snow Instabilities – Multiple Approaches to Lift the Veil

Wet snow avalanches are notoriously difficult to predict, since their formation mechanism is poorly understood and because the material snow is exactly on its melting point and can change its properties suddenly. In order to better understand wet snow a series of methods were applied in the field to investigate wet snow. (1) Ground Penetrating Radar (GPR), which is tied upon a sledge, is used to estimate amount and distribution of liquid water in a seasonal snowpack in an extensive area with a continuous, noninvasive method. (2) Snow profiles and measurements with moisture sensors are used to calibrate the radar measurements. Additionally temperatures and liquid water contents are monitored within the snowpack and in the underlying soil on a steep south facing slope. (3) Artificially triggering of wet snow avalanches – is possible. A review among avalanche professionals in Switzerland and Austria reveals that artificial triggering of wet snow avalanches is common practice.