International Symposium on Mitigative Measures against Snow ...

<strong>International</strong> <strong>Symposium</strong> on Mitigative Measures against Snow Avalanches
Egilsstaðir, Iceland, March 11–14, 2008
Figure 4 shows the effect of possible configuration of a deflecting dam on avalanches in the
size-range from 11 to 14 on the 2D run-out index scale. According to these results, the dam
provides protection for avalanches up to size 12.5 while avalanches of size 13, that is
avalanches that are comparable in size to the January 2005 avalanche, still overflow the dam.
4. CONCLUSIONS
The experience accumulated at IMO indicates that two-dimensional avalanche models are a
useful addition to other methods of studying avalanche motion. The samosAT model seems to
simulate Icelandic avalanches with reasonable realism after an initial calibration and
verification of the model. Avalanches that span a wide size range can be simulated by
changing the bed-friction angle, δ, and the release snow depth, d, concurrently.
The development of the run-out index concept into two-dimensions, together with a definition
of a single parameter axis, simplifies the work. Thereby, the motion of an avalanche, defined
by standard parameters, can be simulated in multiple avalanche paths to estimate the run-out
and other important features. Such simulation results are valuable in cases where records
about avalanche activity are scarce.
Two-dimensional avalanche models have the potential to be an important tool for avalanche
hazard mapping and to aid designers of protective structures.
ACKNOWLEDGEMENT
Hörður Þór Sigurðsson made the map in Figure 3. I thank Tómas Jóhannesson, Harpa Grímsdóttir
and Sigurður Magnús Garðarson for inspiring enthusiasm, patience and guidance.
REFERENCES
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168 Application of two-dimensional avalanche model simulations at the IMO