Lautaret avalanche test site: outcomes from the 11th april 2012 event

The Lautaret full-scale avalanche test site has been used by Cemagref-Irstea since the early 70's. The first studies were dedicated to avalanche released systems. Later, experiments focused on avalanche dynamics and avalanche impact pressures both in relation with the fundamental knowledge of snow flow rheology and the engineering of defense structures and avalanche hazard zoning. Recent instrumentation developments now provide rich-documented in situ measurements of avalanche flow. 20 cm-resolution vertical profiles of pressure and velocity get inside into the internal structure of snow flows with a time sampling rate of 3 kHz. In complement to this Eulerian measurement, the Lagrangian velocity of the avalanche front is measured along the track by digital high-speed stereo-photogrammetry. This remote sensing system also provides the initial surface and volume conditions in the starting zone. These measurements are associated to a 2d shallow water avalanche dynamics model to retrieve best possible rheological parameters (i.e. basal friction law) to be fitted on each avalanche event.