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
Avalanche protection in Austria − present stage and future
development
Siegfried Sauermoser
Austrian Service in Torrent and Avalanche Control, 6020 Innsbruck, Liebeneggstrasse 11, AUSTRIA
e-mail: siegfried.sauermoser (at) die-wildbach.at
ABSTRACT
Protection against natural hazards such as debris flows, land slides or avalanches is as old as
settlement activities in Alpine areas. To look for safe places was the first kind of mitigation
and therefore the oldest houses in a village are normally situated in the safest places. The
number of inhabitants in the mountainous part of Austria and in particular the number of
tourists increased considerably in the last decades. This development leads to a high need for
protection work and nearly 500 km of steel supporting construction were built to protect
settlements and roads against snow avalanches. Several kilometres of avalanche sheds along
roads and a highly developed system in avalanche warning allows winter tourism in valleys
that were close to relocation several decades ago. How does the future of Alpine valleys look?
Beside unknown influences such as socio-economical development and climate change it is
clear that sustainability in protection is necessary. This contains comprehensive mitigation
concepts, the development of an adapted risk culture and a life cycle management of
protection measures.
1. INTRODUCTION
The Alps cover three quarters of the entire Austrian territory, which means that Austria has
the highest share of the Alps of all Central European countries. More than half of the state
territory (83,855 km²) are zones of intensive protection against Alpine natural hazards. Snow
avalanches, debris flows, landslides, floods and rock fall threaten people and their living
space, their settlements and economic activities as well as traffic routes. The growing
settlement pressure and the development of roads in the Alps as well as a strong expansion of
tourism have resulted in an increase of endangered zones over the last few decades. Forests
that grow on the steep slopes of the valleys offer natural protection against these natural
hazards in many ways. This has not always been the case. Excessive timber exploitation for
mining purposes (iron-ore, salt) almost entirely deforested whole valleys in former centuries.
Natural catastrophes of unexpected dimensions were the result. Particularly, the avalanche
disasters in the winter of 1689 were the worst of their kind ever recorded in history. Today
Austria is well equipped with healthy and effective protection forests the state of which is
constantly improved by adequate tending operations. Thus, forests offer an important contribution
to protecting life and space in the Alps. However, there are limits to the protective
capacities of forests. Avalanches, debris flows and storms repeatedly cut large gaps into the
protective forest belts and pave the way for other natural hazards. Protective woods are not
effective against threats that originate above the timer line (1900 – 2100 m a.s.l.) as snow
avalanches are. Most of the starting areas of avalanches are situated between 2000 m –
2400 m a.s.l. Several natural catastrophic events in the last decade such as during the heavy
108 Avalanche protection in Austria − present stage and future development