Avalanche cycles in Austria: an analysis of the major events in the last 50 years

Abstract

During the last 50 years, an average of 30 persons per year was killed by avalanches in Austria. About one-third of all avalanche fatalities occurred as a result of socalled 'catastrophic avalanches'. 'Catastrophic avalanches' are spontaneously released avalanches that affect villages and cause damage to property (buildings, roads and other infrastructure). The biggest avalanche events in Austria were in 1950Austria were in /1951Austria were in (135 fatalities), in 1953Austria were in /1954 and in February 1999, when 38 persons were killed in Galtür and Valzur. This article deals with an analysis of nine major avalanche cycles in the last 55 years. An avalanche cycle in this article is defined as 50 recorded avalanches of at least size 3 in two days and/or 5 persons killed in villages within two days. The basis of this study are the well-documented records from Fliri (1998), who analysed natural disasters in the western part of Austria and the Trentino, including floods, mudflows, earthquakes and avalanches. The meteorological data were taken from two relevant observation sites in the northern part of the Austrian Alps, from two sites in an intermediate and continental region, respectively and from one site in the southern part of the Austrian Alps. Atmospheric patterns were analysed by using weather charts for the relevant periods. Both the meteorological data and the weather charts were provided by the Central Institute for Meteorology and Geodynamics (ZAMG). It was found that there was a major cycle every 6 years (on average). Two-thirds of all investigated cycles were characterised by a continuous increase of snow depth over a period of at least three days. In only three periods (1975, 1986, 1988), daily extreme values could be observed. More than 40% of all the cycles occurred in January. In two-thirds, a north-westerly oriented frontal zone was responsible for the formation of a major cycle. The remaining cycles were released by lowpressure areas over Central Europe and the Mediterranean Sea, respectively.

Effects of climate change on the intensity and frequency of heavy snowfall events in the Pyrenees

“…In general a slight underestimation was observed in the simulated values, except for HSEs in Góriz, where some overestimation occurred. These results are consistent with previous findings of the capacity of RCMs to simulate seasonal precipitation and temperature over the Pyrenees (López-Moreno et al 2008a), magnitude heavy precipitation events and their contribution to total precipitation (López-Moreno and Beniston 2009) and snowpack evolution (López-Moreno et al 2008b, 2009). …”

“…These can disrupt traffic (Datla and Sharma 2008), cause large economic (e.g. collapse of infrastructure) and environmental damage as consequence of the heavy loads of accumulated snow (Strasser 2008), result in injuries and fatalities related to traffic accidents, and increase the frequency of avalanches (Spreitzhofer 2000;Changnon and Changnon 2006;Germain et al 2009;Beniston et al 2003;Höller 2009). Moreover, heavy snowfall followed by melting can trigger large floods that constitute an additional major natural hazard (Changnon and Changnon 2006).…”

Spatial and temporal analysis of fatal off-piste and backcountry avalanche accidents in Austria with a comparison of results in Switzerland, France, Italy and the US

“…of fatal accident events in Austria within the winter periods 1980/1981-2015/2016, which are available from the annual reports of the Austrian Board for Alpine Safety (Kuratorium für alpine Sicherheit, 1973Sicherheit, -2016 and the annual reports of the information services of the federal states (Amt der Tiroler Landesregierung, 1994-2009. In order to check the reliability of the accident data, we performed a cross-check between those reported in the two sources.…”

“…In Austria, about 25-30 fatalities caused by snow avalanches are expected every year (Neuhold, 2012;Höller, 2009). Furthermore, it is reported that in Alpine countries (such as Austria) the number of fatalities is more or less constant over the time (Brugger et al, 2001;Valt and Pivot, 2013;Roth, 2013) and that there is some sort of seasonality in the data in terms of higher frequencies of accidents within a distance of 5 or 6 years (Höller, 2009;Tschirky et al, 2000).…”

“…Furthermore, it is reported that in Alpine countries (such as Austria) the number of fatalities is more or less constant over the time (Brugger et al, 2001;Valt and Pivot, 2013;Roth, 2013) and that there is some sort of seasonality in the data in terms of higher frequencies of accidents within a distance of 5 or 6 years (Höller, 2009;Tschirky et al, 2000). Harvey and Zweifel (2008) even denote that fatalities are decreasing over time in Switzerland.…”