The Landslide Blog is written by Dave Petley, who is widely recognized as a world leader in the study and management of landslides.
In Switzerland, a dramatic rock slope failure is developing above Blatten [46.4128, 7.7987], a village located in Vallais Canton.
Blue News is providing regular updates on a dedicated website. The drama started at the weekend with a major landslide in the Petit Nesthorn area, which impacted and entrained a part of the Birch glacier. This has resulted in evacuation of the majority of the population of Blatten.
There is little doubt that a major instability has developed. The estimated scale of the instable mass is up to 5 million cubic metres. At least 17 metres of displacement have been recorded in the last few days.
Melaine Le Roy is providing detailed coverage of the evolution of the event on BlueSky. Hopefully, you’ll be able to view one of his posts below, which shows the extraordinary scale of the mobile mass:-
And this one, which shows a perspective view:-
There is a webcam of the slope that is capturing images regularly – this is the view at the time of writing. It is clear that the mass is highly mobile, generating a huge volume of rockfall activity as the mass deforms:-
Predicting the development of this failure is extremely difficult. The mass could fail in a large event, or a series of smaller ones, or the rate of movement could slow or even stop (in many ways, that is a poor scenario for the residents of Blatten).
Watch this space.