A new experimental snow avalanche test site at Seehore peak in Aosta Valley (NW Italian Alps)-part I: Conception and logistics

Experimental test sites are important to understand the physical flow processes occurring within an avalanche. They can be at different scale: laboratory or real scale. In Europe, a dozen of real-scale test sites have been realized, though at present only a few of them are still operative. The primary goal is to measure avalanche dynamical variables under controlled conditions. Not all the observed phenomena have been fully understood yet and more work is needed especially regarding small to medium avalanches.The aim of this paper is to present a new experimental test site at a real scale in order to study specific topics: the dynamics of small and medium avalanches, the avalanche release processes and the interaction between avalanche flows and obstacles.The test site, called Seehore, is located in Aosta Valley in the North-western Italian Alps. The slope, with an elevation difference of about 300 m (from 2300 to 2570 m asl), has a mean slope angle of about 28°. Avalanches are artificially released on a routine basis to secure the ski-runs, as the site is located within a ski resort (Monterosa Ski); they are usually dense slab avalanches of small or medium size, but also a powder cloud may occasionally form. The site is instrumented with a steel obstacle, described in details in a companion paper, which measures the effects of avalanches impacting on it. Before, during and after each artificial release physical properties of the snow in the avalanche release, track and deposition zones are recorded; front velocity, erosion and deposition mass are estimated by field surveys or by videogrammetry and terrestrial laser-scan measurements.

► Conception and set up of a new experimental snow avalanche test site in NW Italian Alps ► New possibilities to study the dynamics of small and medium avalanches ► Preliminary analysis of snow and avalanche data of the first two operating seasons