International Snow Science Workshop Proceedings - Montana State University Library

Item: Influence of Summer and Winter Surface Topography on Numerical Avalanche Simulations

• • Title: Influence of Summer and Winter Surface Topography on Numerical Avalanche Simulations

    Proceedings: International Snow Science Workshop Grenoble – Chamonix Mont-Blanc - October 07-11, 2013

    Authors:

    • Maggioni M.  [ DISAFA and NatRisk-LNSA – Università di Torino, Torino – Italy ]
    • Bovet, E.  [ Fondazione Montagna sicura, Courmayeur (AO) – Italy ]  [ DISEG – Politecnico di Torino, Torino – Italy ]
    • Dreier, L.  [ WSL Institute for Snow and Avalanche Research SLF, Davos – Switzerland ]
    • Buehler, Y.  [ WSL Institute for Snow and Avalanche Research SLF, Davos – Switzerland ]
    • Godone, D.  [ DISAFA and NatRisk-LNSA – Università di Torino, Torino – Italy ]
    • Bartelt, P.  [ WSL Institute for Snow and Avalanche Research SLF, Davos – Switzerland ]
    • Freppaz M.  [ DISAFA and NatRisk-LNSA – Università di Torino, Torino – Italy ]
    • Chiaia, B.  [ Fondazione Montagna sicura, Courmayeur (AO) – Italy ]
    • Segor V.  [ Assetto idrogeologico dei bacini montani – Ufficio Neve e Valanghe della Regione autonoma Valle d’Aosta, Quart (AO) – Italy ]

    Date: 2013-10-07

    Abstract: Numerical avalanche dynamics models are widely used to calculate extreme avalanches for hazard mapping and mitigation measure planning. A basic model input is the terrain represented by Digital Elevation Models (DEM). Usually summer topography is used as model input, even though most avalanches run on snow-covered terrain with filled gullies and smoothed roughness. Moreover, the deposits of previous avalanche events can significantly influence the dynamics of following events, especially considering frequent avalanches on the same path. The aim of this paper is to analyze the outputs of the avalanche dynamics model RAMMS obtained using DEM input from summer compared to Digital Surface Model (DSM) generated in winter by laser scanning and digital photogrammetry. We use the 2D model RAMMS to calculate avalanches in two study areas: Seehore test site in Aosta Valley (IT) and Davos (CH). At the Seehore test site we analyze two small artificially triggered avalanches. In those occasions, we performed terrestrial laser scanning (TLS) and photogrammetry before and after the events, to get information on the avalanche volume and on the snow cover distribution before the event. Previous deposits clearly influence the dynamics of the avalanche flow, mainly the direction and the deposition pattern. Simulations on the summer DEM do not consider them, while simulations on the winter DSM are closer to reality. In the Davos area we analyze two avalanche paths and calculate two avalanche events on summer DEM as well as on winter DSM data generated by airborne digital photogrammetry. We find slight differences in flow velocity as well as in flow path of the simulated avalanches. In particular, snow filled gullies are relevant for the avalanche path. In this work we present the results obtained in these two study areas and draw general conclusions about this important and not yet developed issue.

    Object ID: ISSW13_paper_O1-21.pdf

    Language of Article: English

    Presenter(s): Unknown

    Keywords: avalanche modelling, surface topography, running surface, uncertainty

    Page Number(s): 591-598

    Subjects: snow model topography artificially triggered avalanches

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