23 August 2016

Kleine Gaisl: a large rockfall in the Italian Dolomites

Posted by dr-dave

Kleine Gaisl rockfall

Kleine Gaisl (Piccola Croda Rossa), is a large (2859 m) mountain in the Braies Valley in the South Tyrol in the northern Italian Dolomites. At the end of last week a large rockfall occurred in a series of stages over two days between 18th and 20th August.  There is a good report on Planet Mountain, although they have the volume wrong by three orders of magnitude. From other sources the estimated volume is 600,000 to 700,000 cubic metres.

Mountain guide Roman Valentini captured a part of the rockfall in a video that has been uploaded to Youtube.  But note that this is not the main collapse event, as Planet Mountain notes:

The footage below was filmed by Roman Valentini, a mountain guide working for Alta Badia Guides, who was in the area on Thursday, August 18 at around 12:30. Although this is only the first, smaller part of the landslide, Valentini told planetmountain.com “It was ‘spectacular’ … I’ve never seen anything quite like it. It looked like a river in spate, with rocks half the size of houses tumbling down.”

Although the main rockfall event occurred later (the seismic data will be interesting here in order to understand the sequence of events), there is a significant collapse event at about three minutes into the video:

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The rockfall had been anticipated as a large tension crack had been observed prior to the collapse event.  Stol.it has a nice article, in German, though Google Translate does a good job, that includes an interview with the Deputy Mayor, Erwin Steiner, which also includes this good image of the source area of the rockfall:

Kleine Gaisl

The rockfall scar on Kleine Gaisl, image by Erwin Steiner

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Whilst another article on the same site has another view of the source zone that also captures some of the rockfall deposit::

Keliene Gaisl

Image of the Kleine Gaisl rockfall zone, including a part of the deposit. Image by Tourismusbüro Prags