The aim of this study is to quantify climatic trends over the past six decades at three elevation levels in order to assess their effect on wet snow avalanche activity for the Kaprun Valley, Austria. For this purpose, we analyze links between meteorological and avalanche data by comparing days with and without avalanches. We quantify seasonal (Nov-May) and monthly trends by using Mann-Kendall trend statistics. Seasonal air temperature variables increased significantly within the 1980s and 1990s at all three elevation levels. This increase is mostly connected to the minimum air temperature and most pronounced in the months from November to February. Consequently, these trends are reflected in a shift of about 250m of the seasonal snowline towards higher elevation levels since the 1980s. The months February, April and May reveal a maximum shift of about 500m. Furthermore, our results show increasing trends in the number of rainfall days at low and mid-altitudes, and a decrease in the number of snowfall days, respectively. Linking meteorological data with avalanche data revealed a significant impact of air temperature, 5-day sums of positive air temperature and 1-day sum of rainfall for wet snow avalanche active and non-active days, whereas the trend for 5-day sums of rain was not significant. Trends in wet snow avalanche activity remain inconclusive.
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