Permafrost is the term used to describe ground that is frozen all year round.Not just superficially, but to greater depths.
In the (Swiss) Alps, permafrost can occur at shady locations from an altitude of about 2500m above sea level.
During the summer months, the top layer of permafrost thaws and freezes again at the end of autumn.
For the layman it is not easy to recognize in which soils permafrost is present and in which it is not. An idea can be obtained by looking at the
permafrost indication map on map.admin.ch (Official maps of Switzerland).
As a result of global warming, permafrost is disappearing like glaciers. This is less visually noticeable than the melting of glaciers.
The disappearance of permafrost has the following negative consequences, among others:
1) Permafrost stabilizes soils and rocks.
When permafrost melts, slopes and rock faces lose stability. Landslides, rock and landslides, and debris flows can result.
In the Alps, this leads to problems for settlements (e.g. villages like Randa and Kandersteg), traffic routes (e.g. railroad lines, roads), tourist infrastructure (e.g. cable car stations and masts) and mountain huts (e.g. the two SAC huts Rothornhütte and Mutthornhütte).
2) In the tundra (e.g. in Siberia), permafrost binds, among other things, large amounts of the greenhouse gas methane.
If permafrost melts in the tundra, methane is released, which additionally drives global warming (= positive feedback).
In the interest of all, it is therefore very important that global warming is limited as quickly as possible, e.g. through changes in people's behavior and through technical measures.
Landslide at Spitze Stei above Kandersteg. Photo from 1.9.2021
Several million cubic meters of rock slide from approximately top left to bottom right. To the right of the orange dots, the eastern incipient line can be seen. Dwindling permafrost plays a role in this event. The consequences of a large landslide threaten parts of the village of Kandersteg. In recent years, large protective structures have been built.
Spreitgrabe debris flow near Guttannen, Bernese Oberland. Photo from 20.08.2010
In the rock faces and steep slopes above the Spreitgraben, dwindling permafrost, among other things, led to instability of the terrain. During/after heavy precipitation, several partly very large debris flows occurred, threatening the gas transit line and partially damaging the gallery of the road to Guttannen (and to the Grimsel Pass). Further down, a residential house had to be abandoned and deconstructed.
Published:
08.06.2022
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