Study at LTER site Obergurgl in Austria reveals destabilizing effects of climate change on the rock glacier in Äußeres Hochebenkar
4 August 2023
Rock glaciers are complex structures of boulders and debris held together by a frozen permafrost core. Due to their characteristic appearance, they are probably the most impressive permafrost phenomena in the high mountains. Rock glaciers, like ice glaciers, are strongly influenced by the climatic changes of the last decades. This may lead to alarming developments, as shown by an international team of researchers, monitoring the rock glacier in Äußeres Hochebenkar near Obergurgl.
The time series shows two cycles of destabilisation in the lower section of the rock glacier. The first lasted from the early 1950s until the mid-1970s. The second began around 2017 after approximately 2 decades of more gradual acceleration and is currently ongoing. Both destabilisation periods are characterised by high velocities and the development of morphological destabilisation features on the rock glacier surface.
Acceleration in the most recent years has been very pronounced, with velocities reaching 2030 m a 1 in 2020–2021. These values are unprecedented in the time series and suggest highly destabilised conditions in the lower section of the rock glacier, which shows signs of translational and rotational landslide-like movement.