1. WSL Institute for Snow and Avalanche Research SLF; Davos Switzerland
2. Geological Institute; ETH Zurich; Sonnegstrasse 5 8092 Zürich Switzerland
3. Department of Geosciences; University of Fribourg; Chemin du Musée 4 1700 Fribourg Switzerland
4. EAWAG, Swiss Federal Institute of Aquatic Science and Technology; Duebendorf Switzerland