Dating of recent avalanche events in the Eastern High Sudetes, Czech Republic

Abstract

This article deals with recent avalanche events dated by the dendrogeomorphic method and their verification. The research was focused on two active mid-mountain avalanche sites – the Sněžná kotlina Hollow and the Morava Hollow in the Eastern High Sudetes. A total of 96 trees were analysed and eight highly probable avalanches were identified since 1924 and 1935, respectively. The avalanche events were verified using historical aerial photographs, meteorological data and different historical sources (i.e. local newspapers, historic photographs, etc.). Avalanches are more frequent in the Sněžná kotlina Hollow (avalanche years: 1984, 1993, 2004, 2005, 2007, 2008) than in the Morava Hollow (avalanche years: 1942, 1999). Most avalanche events correspond with heavy snowfall events or high temperature events during February and March. There are significant differences in the frequency of avalanches between the two study sites that are reflected in the morphology of the avalanche paths under study. The more active avalanche path has a more ragged surface and includes a typical avalanche gully. The results of the verification support the use of the dendrogeomorphic method because the potential avalanche events were clearly confirmed.