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
Application of two-dimensional avalanche model simulations at
the Icelandic Meteorological Office
Eiríkur Gíslason
Icelandic Meteorological Office, Bústaðavegi 9, IS-150 Reykjavík, ICELAND
e-mail: eg (at) vedur.is
ABSTRACT
The Icelandic Meteorological Office (IMO) has used two-dimensional avalanche models for
various applications since the year 2000. This paper summarises some results of this work
and briefly outlines methods and operational guidelines that have been established. The IMO
has been running the samosAT model for a couple of years following an initial calibration and
verification. The concepts developed at IMO, of a standard path and run-out index scale for
the run-out distance of avalanches, have now been expanded into two dimensions using
samosAT. Model parameters that allow simulation of avalanches over a wide size range have
been specified. This simplifies the operation of the model and allows comparison of results
for different avalanche paths. It also allows a more systematic use of 2D models in hazard
mapping and other applications that require study of avalanche motion. Examples of such
applications are described.
1. INTRODUCTION
The SAMOS model was developed for the Austrian Avalanche and Torrent Research Institute
in Innsbruck by the consulting company AVL in Graz (Zwinger and others, 2003). Initially,
an earlier version of the model, now referred to as SAMOS99, was used at IMO and the
model runs were performed at AVL. Before that work commenced, the model was run for the
catastrophic avalanche from Skollahvilft at Flateyri in northwest Iceland in 1995 in order to
check the applicability of the parameter values that are traditionally adopted for the model in
Austria. It was concluded from these runs that the same input parameters can be used for the
SAMOS99 model for Icelandic conditions as are traditionally used in Austria (Jóhannesson
and others, 2001).
A new version of the SAMOS model has now been introduced, referred to as samosAT. The
IMO has been running this version of the model for a couple of years. The application of the
new samosAT model version at the IMO was initiated with a study of the performance of the
model for several well known Icelandic avalanches and a comparison of simulations of the
new model with simulations of SAMOS99. For this purpose, the avalanche path of Skollahvilft
at Flateyri was again of great significance because of the well-known avalanche history
and the earlier modelling attempts. It was found that the default parameters of samosAT, with
the “samos classic” fiction model, did not give good results for the Icelandic avalanches that
were modelled. After calibration and verification of the model, a recommended set of model
parameters to be used in Iceland was established (Gíslason and Jóhannesson, 2007).
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