Flims Rockslide and Expected Consequences of Climate Change on Slope Stability
Luogo della manifestazioneviewing platform of Conn near Flims
36. Treffen der Parlamentarischen Gruppe «Klimaänderung» vom 4 October 2006 in Flims
Given the opportunity of a special setting the parliamentary meeting took place at the viewing platform of Conn near Flims, from where one has an spectacular view on the Rheinschlucht. About 40 members of the parliament and invited guests from governmental agencies attended the meeting.
Prof. Adrian Pfiffner from the University of Bern explored the processes of bedrock in general and of the area around Flims in particular. About 8400 years ago the Flims rockslide, which is considered to be the biggest rockslide to have happened in the Alps, occurred. The trigger of the event is not entirely clear: The rockslide may have been caused by heavy rainfalls or by an earthquake. 9 km3 of rock barricaded the valley and dammed up the Vorderrhein at Ilanz/Glion. Eventually the water cut a curb into the dam and gushed into the Churer Rheintal. The event had an impact as far as Lake Constance.
Dr. Roland Hohmann from the OcCC (Advisory Body on Climate Change) related the occurrence of slope instabilities to changes of the water cycle, of glaciers and permafrost with temperature as a key indicator. If the temperature is above the zero point, in the mountains there is rain instead of snow. If there is continued warming the glaciers melt and the valley slopes loose their stabilizing support. At the same time permafrost thaws and the coherence of rock and soil diminishes. How does climate change affect the occurrence of rockfalls and landslides? Roland Hohmann summarised the changes expected until 2050.