Dear researchers, various mountain villages in Switzerland have been repeatedly threatened by landslides in recent years. I wonder how many places in the Alps are at risk due to thawing permafrost, and whether a mountain always collapses when permafrost thaws.
As alpine permafrost thaws, major rockfalls occur on only a few mountains – accounting for a few per cent of the total. Detailed data on this can be obtained via the PERMOS network (Dr Jeanette Nötzli).
A mountain does not collapse “like a pile of sand”. Rock always detaches at geologically formed weak points, which in some cases have been stabilised by the permafrost but are now thawing in part under the current climate.
In addition, there are numerous landslides that are not influenced by permafrost – such as the landslide in Brienz / Brinzauls or in the Gürbetal.