Preprints
https://doi.org/10.5194/nhess-2022-97
https://doi.org/10.5194/nhess-2022-97
 
05 Apr 2022
05 Apr 2022
Status: this preprint is currently under review for the journal NHESS.

The impact of terrain model source and resolution on snow avalanche modelling

Aubrey Miller1, Pascal Sirguey1, Simon Morris2, Perry Bartelt3,4, Nicolas Cullen5, Todd Redpath5,1, Kevin Thompson2, and Yves Bühler3,4 Aubrey Miller et al.
  • 1National School of Surveying, University of Otago, P.O. Box 56, Dunedin, New Zealand
  • 2Downer NZ Ltd, Milford Road Alliance, Te Anau, New Zealand
  • 3WSL Institute for Snow and Avalanche Research SLF, Flüelastrasse 11, 7260 Davos Dorf, Switzerland
  • 4Climate Change, Extremes and Natural Hazards in Alpine Regions Research Center CERC, Flüelastrasse 11, 7260 Davos Dorf, Switzerland
  • 5School of Geography, University of Otago, Dunedin, New Zealand

Abstract. Natural hazard models need accurate digital elevation models (DEMs) to simulate mass movements on three-dimensional terrain. A variety of platforms (terrestrial, drones, aerial, satellite) and sensor technologies (photogrammetry, LiDAR, interferometric synthetic aperture radar) are used to generate DEMs at a range of spatial resolutions with varying accuracy. As the availability of high-resolution DEMs continues to increase and the cost to produce DEMs continues to fall, hazard modellers must often choose which DEM to use for their modelling. Here we use current state-of-the-art sensor technologies (satellite photogrammetry and terrestrial LiDAR) to generate high-resolution DEMs and test the sensitivity of the Rapid Mass Movements Simulation software (RAMMS) to the DEM source and spatial resolution for simulating a large and complex snow avalanche along Milford Road in Fiordland, Aotearoa New Zealand. Holding the RAMMS parameters constant while adjusting the source and spatial resolution of the DEM reveals how differences in terrain representation between the satellite photogrammetry and terrestrial LiDAR DEMs (2 m spatial resolution) affect the reliability of the simulation estimates (e.g., maximum core velocity, powder pressure, final debris pattern). At the same time, coarser representations of the terrain (5 m, 15 m spatial resolution) produce simulated avalanches that run too far and produce a powder cloud that is too large, though with lower maximum impact pressures, compared to the actual event. The complex nature of the alpine terrain in the avalanche path (steep, rough, rock faces, tree-less) made it a suitable location to specifically test the model sensitivity to digital surface models (DSMs) where both the ground and above-ground features on the topography are included in the elevation model. Combined with the nature of the snowpack in the path (warm, deep with a steep elevation gradient) lying on a bedrock surface and plunging over a cliff, RAMMS performed well in the challenging conditions when using the high spatial-resolution 2 m DSM.

Aubrey Miller et al.

Status: final response (author comments only)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on nhess-2022-97', Anonymous Referee #1, 25 Apr 2022
  • RC2: 'Comment on nhess-2022-97', Anonymous Referee #2, 02 May 2022

Aubrey Miller et al.

Aubrey Miller et al.

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Latest update: 24 May 2022
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Short summary
Natural hazard modellers simulate mass movements on three-dimensional terrain to better anticipate the risk to people and infrastructure. These simulations require accurate digital elevation models. We test the sensitivity of a well-established snow avalanche model (RAMMS) to the source and spatial resolution of the elevation model. We find key differences in the representation of terrain greatly affect the simulated avalanche results, with implications for hazard planning.
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