Avalanche risk assessment – a multi-temporal approach, results from Galtür, Austria

Abstract

Abstract. Snow avalanches pose a threat to settlements and infrastructure in alpine environments. Due to the catastrophic events in recent years, the public is more aware of this phenomenon. Alpine settlements have always been confronted with natural hazards, but changes in land use and in dealing with avalanche hazards lead to an altering perception of this threat. In this study, a multi-temporal risk assessment is presented for three avalanche tracks in the municipality of Galtür, Austria. Changes in avalanche risk as well as changes in the risk-influencing factors (process behaviour, values at risk (buildings) and vulnerability) between 1950 and 2000 are quantified. An additional focus is put on the interconnection between these factors and their influence on the resulting risk.The avalanche processes were calculated using different simulation models (SAMOS as well as ELBA+). For each avalanche track, different scenarios were calculated according to the development of mitigation measures. The focus of the study was on a multi-temporal risk assessment; consequently the used models could be replaced with other snow avalanche models providing the same functionalities. The monetary values of buildings were estimated using the volume of the buildings and average prices per cubic meter. The changing size of the buildings over time was inferred from construction plans. The vulnerability of the buildings is understood as a degree of loss to a given element within the area affected by natural hazards. A vulnerability function for different construction types of buildings that depends on avalanche pressure was used to assess the degree of loss. No general risk trend could be determined for the studied avalanche tracks. Due to the high complexity of the variCorrespondence to: M. Keiler (margreth.keiler@univie.ac.at) ations in risk, small changes of one of several influencing factors can cause considerable differences in the resulting risk. This multi-temporal approach leads to better understanding of the today's risk by identifying the main changes and the underlying processes. Furthermore, this knowledge can be implemented in strategies for sustainable development in Alpine settlements.

Regional evaluation of three day snow depth for avalanche hazard mapping in Switzerland

“…Salm et al, 1990;Barbolini et al, 2004) and management of the risk therein (e.g. Bründl et al, 2004;Fuchs et al, 2004;Fuchs and McAlpin, 2005;Keiler et al, 2006). The current approaches to avalanche hazard mapping couple avalanche dynamics modelling (Salm et al, 1990;Harbitz, 1998;Bartelt et al, 1999;Ancey et al, 2004) with statistical analysis of snow depth at the avalanche starting zone (Burkard and Salm, 1992;Hopf, 1998;Barbolini et al, 2002).…”

Mountain hazards: reducing vulnerability by adapted building design

“…In parallel, the arising discussion related to possible impacts of climate change on the magnitude and frequency of mountain hazards (Keiler et al 2010) resulted in a rising scientific debate on the spatiotemporal evolution of elements at risk exposed (e.g., Hufschmid et al 2005;Fuchs and Bründl 2005;Keiler et al 2006). As a consequence it may be postulated that risk awareness of the general public and administrative bodies responsible for hazard protection has risen (Commission of the European Communities 2007).…”

“…Recently, promising approaches for a quantification of vulnerability have been made by Wilhelm (1997), Borter (1999), Barbolini et al (2004) and Keiler et al (2006) with respect to avalanches and rock fall processes, respectively. However, sound suggestions for landslides and torrent processes are still largely unavailable, even if these processes caused major losses in the Alps in the recent years (Fuchs et al 2007a;Fuchs 2009;Totschnig et al 2011).…”

Towards dynamics in flood risk assessment

“…It has repeatedly been claimed that there is a particular lack of studies related to the temporal evolution of risk (Keiler et al, 2006;Fuchs andKeiler, 2008, 2013;Fuchs et al, , 2012a, and the underlying vulnerability of values at risk and of communities (Fuchs, 2009;Fuchs et al, 2011Fuchs et al, , 2012bPapathoma-Köhle et al, 2011). Therefore, based on the static and dynamic formalisations of vulnerability presented in the previous section, we introduce the static and dynamic notions of risk.…”

“…Moreover, one fundamental characteristic of mountain catchments is a temporal dynamic in sediment availability, which results in highly variable discharge behaviour. Secondly, the elements at risk exposed change over time, which results in a long-term increase for many mountain communities in Europe and a superimposed short-term fluctuation due to people commuting into these mountain regions (Fuchs et al, 2004Keiler, 2004;Keiler et al, 2005Keiler et al, , 2006Zischg et al, 2005).…”