Comparison of avalanche-velocity measurements by means of pulsed Doppler radar, continuous wave radar and optical methods

Velocities of mixed dense-flow/powder-snow avalanches have been measured by means of pulsed Doppler radar and by continuous wave radar at the full scale avalanche test site Vallée de la Sionne. From the radar data, we derive velocities of the saltation layer and of the powder part of the avalanche. The results obtained by the two different radar measurement techniques are compared and also are checked against the velocity data obtained by opto-electronic velocity sensors installed at different heights on the 20 m high mast in the avalanche track and against videogrammetry velocity data. We demonstrate that the measurements are consistent and discuss how information about the avalanche structure can be derived from the measurements.