10 February 2014
Three interesting new videos – a slow avalanche, a coastal rockslide and a quarry slide
Posted by Dave Petley
1. A slow avalanche in Italy
Whilst I don’t usually feature snow avalanches on this blog, this one is worth a look. It is a slow avalanche (the picture above is a screenshot from the film) that was captured a few days ago in Passeiertal in Sudtirol, Italy and is on Youtube:
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The interesting aspect of this avalanche is the transition from a rapid flow into a creeping slide. Note the enormous momentum behind the slow phase of the avalanche,which was able to fell trees and small buildings with ease. The larger buildings must be very well-built! It is interesting to note the similarities with the transition in the Mount Dixon rock avalanche from last year (see my posts here and here), which also transitioned from a flow to a creeping mass:
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Several people brought this one to my attention – thanks to you all.
2. A small landslide from Devon
This small landslide was captured at Lusty Glaze (what a great name!) on the coast of Devon in SW England on 1st February:
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3. A rockslide in a quarry
Thanks to Thomas Hodgson for pointing out this video, which has been online for over three years but had passed me by. It is not clear where it happened, as the commentary says only: “Textbook example of footwall failure / collapse in a coal mine on a previously unidentified fault plane.”
Dave Petley is the Vice-Chancellor of the University of Hull in the United Kingdom. His blog provides commentary and analysis of landslide events occurring worldwide, including the landslides themselves, latest research, and conferences and meetings.
This avalanche/slide has the same “tentacled” look as the recent one in Alaska that blocked a valley, isolating Valdez. I thought I was seeing things, but the same structures in Alaska created free-form curving “pincers” where they rode out. Reminiscent of debris flows: a mobile core and snout, confining nevees on either side. I wonder what the “lubricating” agent is? Localized, momentary thawing at points of contact, like an ice skater?