19 June 2023
An update on the 11 June 2023 Flüchthorn rock avalanche
Land Tirol has published (in German) some information about the 11 June 2023 Flüchthorn rock avalanche in Austria. Most interestingly, they have collected aerial laser scanning of the mountain, which has allowed an estimate to be made of the volume of the landslide, which is reckoned to be 1 million cubic metres. There ae two particularly interesting graphics. First, one highlighting the volume of rock that has been lost:-
Second is an initial cross-section, also using the laser scan data, showing the change in topography:-
The southern peak of the mountain has reduced in elevation by 19 m, from 3,399 m to 3,380 m, and the mountain top has been displaced laterally by about 30 m. This event is unusual, but not unique, in cleaving through the summit in this way.
The best image that I have seen of the whole of the landslide has been released by Land Tirol:-
Note the very steep initial fall of the landslide, then the runout over a terrace, before a steep descent into the lake. There will undoubtedly be modelling undertaken of this event, which will be published in due course. It is very fortunate that there was no-one in the path of this major rock avalanche.
Finally, Micha Dietz has published some further seismic analyses of the event, which is worth reading. It is interesting to see how different stations captured different elements of the seismic signal generated by this landslide.