Lawine Galtür 1999

Snow Avalanche Calculation in Austria Galtür, natural disaster 23.02.99

The avalanche and its assumptions calculated by the GfsRiver modul of Stéphane Popinet.
The exteme situation of snowfall (10´th day snowfall 2.43m) leeded to the avalanche on 23.02.1999.
The release Area width was 400m wide and above 45˚ steep at the hight of 2700m.

Figure 1) Galltür in the winter season, flight picture (from the Internet)

Flow Resistance Law:
I’ ve tried to setup the VOELLMY rheology described at RAMMS [1]

Sw = µ * ρ * H * g * cos (φ) + ( ρ * g * U * U ) / ξ
Sa = ρ * H * g * sin (φ)
S = Sa − Sw
S = ρ * g * H * ( ( sin(φ) − µ * cos(φ) ) − U * U / ξ )

Where S a stand for the frictional resistance, µ for the Coulomb type friction H for the thickness
of the fluid layer, ρ is the density, g the gravitational acceleration, φ the topographic gradient, U the
velocity and ξ a coefficient controlling the velocity squared drag.

Figure 2: Site-Map of Galtür [10].

Parameters for the calculation:

SLand = fabs ( cos ( atan ( sqrt ( dx(”Zb”) * dx(”Zb” ) + dy(”Zb”) * dy(”Zb”) ) ) ) )
for derivatives write dx(”U”)
SLcos = cos(atan(sqrt(dx(”Zb”) ∗ dx(”Zb”) + dy(”Zb”) ∗ dy(”Zb”))))
Voellmy gliding parameter depends on hights of the elevation (land cover).
The results are visualised in the imagess (Figure 1) and (Figure 2) generated in the analyses. The
diagram of the Sliding Parameters can found in (Figure 4) on the end of the document. To stop the
avalanche sooner a further Parameter α is included like it is done in the new version of SamosAT [2].

Figure 3: GERRIS Result P (Snowhights) with Paraview on Google [4] and TIRIS [8] T=64sec

Figure 4: Galtür Site-Map from TIRIS and the article [7]

A description of a calculation with SamosAT and judgments of the procedure can be found in [5].

Figure 5: Voellmy-Parameters shown in the Gliding Factor, related to the Analyses.

References:

[1] Ramms Avalanche Modul: Technical Report, WSL Institute for Snow and Avalanche
     Research SLF and the Swiss Federal Institute for Forest, Snow and Landscape Research
     WSL.
[2] SamosAT: AVL Graz. Technical Report, AVL List GmbH, Austria.
[3] Stephane Popinet: Gerris Flow Solver, GPL license. Technical Report, NIWA (Na-
     tional Institute of Water and Atmospheric Research, Institut Jean le Rond d’Alembert),
     2012.
[4] Google-Maps: Grafiken 2014 cnes/spot image, digitalglobe, geoimage austria Landsat,
     Kartendaten 2014 Google-Map by Qgis used by R.Promper. http.//maps.google.at
[5] Gerhard Volk & Karl Kleemayr: Integration von dynamisch variablen Fliesspa-
     rametern in ein 2D Voellmy Lawinenmodell. International Symposion, Interpraevent 2000
   - Villach, Austria.
[6] M. Keiler: Development of the damage potential resulting from avalanche risk in the
     period 1950 - 2000, case study Galtur. Institute of Geography, University of Innsbruck,
     Innrain 52, A-6020 Innsbruck, Austria. Natural Hazards and Earth System Sciences
     (2004) 4, 249 - 256.
[7] Johann Stötter & Gertraud Meissl & Michael Rinderer & Margreth
     Keiler & Sven Fuchs: Eine Gemeinde im Zeichen des Lawinenereignisses von 1999.
     Institut für Geographie der Universität Innsbruck.
[8] Tiroler Rauminformationssystem (Hrsg).(2009): Tiroler Landesregierung.
     Abteilung Landesentwicklung und Zukunftsstrategie Heiliggeiststrasse 7-9, 6020 Inns-
     bruck. Ausschnitt um Galtür. https://www.tirol.gv.at/statistik-budget/tiris-kartendienste/
[9] Stéphane Popinet. GERRIS flow solver, GPL License.
     Technical Report, NIWA (National Institute of Water and Atmospheric Research,
     Institut Jean le Rond d’Alembert), 2012.
[10] TIRIS. Tiris. TIRIS Tiroler Geographisches Informationssystem, ALS Befliegungen 2009.