Journal cover Journal topic
Natural Hazards and Earth System Sciences An interactive open-access journal of the European Geosciences Union
Journal topic

Journal metrics

Journal metrics

  • IF value: 2.281 IF 2.281
  • IF 5-year value: 2.693 IF 5-year 2.693
  • CiteScore value: 2.43 CiteScore 2.43
  • SNIP value: 1.193 SNIP 1.193
  • SJR value: 0.965 SJR 0.965
  • IPP value: 2.31 IPP 2.31
  • h5-index value: 40 h5-index 40
  • Scimago H index value: 73 Scimago H index 73
Volume 15, issue 6 | Copyright
Nat. Hazards Earth Syst. Sci., 15, 1275-1288, 2015
https://doi.org/10.5194/nhess-15-1275-2015
© Author(s) 2015. This work is distributed under
the Creative Commons Attribution 3.0 License.

Research article 18 Jun 2015

Research article | 18 Jun 2015

Forest damage and snow avalanche flow regime

T. Feistl1,2, P. Bebi1, M. Christen1, S. Margreth1, L. Diefenbach3, and P. Bartelt1 T. Feistl et al.
  • 1WSL Institute for Snow and Avalanche Research SLF, Flüelastrasse 11, 7260 Davos Dorf, Switzerland
  • 2Technical University Munich (TUM), Engineering Geology, Arcisstrasse 21, 80333 Munich, Germany
  • 3Swiss Federal Institute of Technology (ETH), Rämistrasse 101, 8092 Zurich, Switzerland

Abstract. Snow avalanches break, uproot and overturn trees causing damage to forests. The extent of forest damage provides useful information on avalanche frequency and intensity. However, impact forces depend on avalanche flow regime. In this paper, we define avalanche loading cases representing four different avalanche flow regimes: powder, intermittent, dry and wet. Using a numerical model that simulates both powder and wet snow avalanches, we study documented events with forest damage. First we show that in the powder regime, although the applied impact pressures can be small, large bending moments in the tree stem can be produced due to the torque action of the blast. The impact area of the blast extends over the entire tree crown. We find that, powder clouds with velocities over 20 m s-1 can break tree stems. Second we demonstrate that intermittent granular loadings are equivalent to low-density uniform dry snow loadings under the assumption of homogeneous particle distributions. The intermittent regime seldom controls tree breakage. Third we calculate quasi-static pressures of wet snow avalanches and show that they can be much higher than pressures calculated using dynamic pressure formulas. Wet snow pressure depends both on avalanche volume and terrain features upstream of the tree.

Publications Copernicus
Download
Short summary
Snow avalanches break, uproot and overturn trees, causing damage to forests. In this paper, we define avalanche loading cases representing four different avalanche flow regimes: powder, intermittent, dry and wet. Using a numerical model that simulates both powder and wet snow avalanches, we study documented events with forest damage. We find that powder clouds with velocities over 20m/s break tree stems and that quasi-static pressures of wet snow avalanches are much higher than dynamic pressure.
Snow avalanches break, uproot and overturn trees, causing damage to forests. In this paper, we...
Citation
Share