5 October 2016
Aletsch: a major developing post-glacial rockslide
Posted by Dave Petley
Aletsch: a major developing glacial rockslide
Both Juy Bullot and Eric Bardou (many thanks to them) have alerted me to a very interesting major rockslide developing in the Aletsch region of Switzerland. Reports about the slide are only in French as far as I can tell, but this is a most interesting landslide.
The slide itself is at Moosfluh in the Riederalp, Canton du Valais, above the left flank if the Aletsch Glacier. This is a Google Earth image of the site, although note that the image is seven years old:
Le Nouvelliste has a brief article on the landslide (in French of course). this is my translation, with help from Google because I’m lazy!,:
A landslide in Moosfluh on the left bank of the Aletsch glacier has greatly accelerated in recent weeks. The hiking trails in the sector have been closed by the municipality of Riederalp with support from the canton. Numerous cracks and a few rockfalls have been observed at Moosfluh on the left bank of the Aletsch glacier. The phenomenon is being monitored in detail. The area concerned is about 1 square kilometre. The moving mass has a volume of more than 200 million cubic metres and is moving more than 20 cm per day.
A rapid collapse of the entire mass seems at this stage very unlikely.
They have this image of the site:
Rhone FM has a view from a different angle:
This is a wonderful opportunity to study the development of progressive failure in a large rockslope. Predicting the time of failure is fraught with difficulty, and it is good that no bold forecasts are being made at this stage. A particularly interesting aspect of this landslide is that its location is close to the terminus of the retreating Aletsch Glacier. Wikipedia reports that in some years this glacier is retreating at 100 m per year. It has long been hypothesised that major rockslides may be more likely when slopes are debuttressed by glacial retreat. That may be the case here.
Other posts on a similar topic
- Glacier Bay Landslide in Alaska: a satellite image and new videos
- Lamplugh Glacier rock avalanche: A massive new landslide in Alaska on Tuesday
- The Tyndall Glacier landslide: images from the University of Alaska Fairbanks
- The Tyndall Glacier landslide in Alaska: the largest recorded non-volcanic landslide in North America
- Dariali Gorge: another very large landslide from the Devdoraki glacier
- The Siachen Glacier avalanche (138 people killed) was an ice-rock avalanche