Lawine Häusling 2013

Snow Avalanche Calculation in Austria Tirol Häusling (Power-House)

Author             : Reinhard Promper
Command         : gerris2D Aval_Haeuslg.gfs | gfsview2D h3D1.gfv,
                             for DEM-Model conv.: asci2xyz.awk < TIRIS Haeuslg 10m CaGer.asc | xyz2kdt -v etopo11
Version            : 1.0.1
Required files : Aval_Haeusling.gfs, asci2xyz.awk, TIRIS Haeuslg 10m CaGer.asc, h3D1.gfv
Running time   : 10 minutes, September 2013.

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 270

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 1: Map with the situation “Breitensteinaste” and the blue avalanche registration lines from TIRIS [8].

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 pictures (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 2: GERRIS Result P (Snowhights) Mayavi2 on Google [4] and TIRIS [8] T=52sec, little Pict. top left [11]

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

Figure 3: Voellmy-Parameters shown in the Gliding Factor, related to the Analyses.

References: