1Eidgenössiche Technische Hochschule Zürich (ETHZ), ETH Hönggerberg, LEP, IRL: HIL H32.1, 8093 Zürich, Switzerland
2WSL Swiss Federal Institute for Snow and Avalanche Research, Research Unit Ecosystem Boudaries, 7260 Davos, Switzerland
3Department of Civil and Environmental Engineering, University of California, Berkeley, CA 94720-1710 USA