7 September 2020

The Koidern landslide: a long runout event in Canada

Posted by Dave Petley

The Koidern landslide: a long runout event in Canada

Apologies for the lack of posts of late – due to Covid-19, and its associated secondary hazards, my day job is taking all of my time at the moment.  Anyway, on Saturday Brent Ward tweeted a fantastic set of aerial images of the Koidern landslide, in the Yukon of Canada.  This is one of the most spectacular landslides of the year to date:-

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Brent has posted a thread of images of the Koidern landslide, which includes this pair of tweets showing the structure of the landslide (mollards are cones of rock avalanche material) and the landslide dam:-

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The Koidern landslide is a very interesting rock avalanche, showing quite high mobility.  Note the very clear main track of the landslide, as well as the areas on either with lower levels of debris.  It appears to me that a part of the landslide has super-elevated on the outside of the first bend.  Some landslide debris has also spilled out on the true right side of the track.

The images show that the landslide dam has overtopped; given its size and the remote location the hazard is very low.

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Quickslide 1: A spectacular rockfall at Cima Canali at Pale di San Martino in the Dolomites

This is a pretty cool video of a recent rockfall.  Note the very large boulder that leaves the dust cloud on the right hand side and disappears down the valley:-

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Quickslide 2: Landslides from Typhoon Haishen in Japan

Typhoon Haishen swept across Japan over the weekend.  At least one substantial landslide has been reported.  The Mainichi reports:

A woman in her 60s and her son in his 30s as well as two Vietnamese male interns were reported missing and a man in his 70s broke his ribs after a mudslide struck a construction firm office, which was also used as a residence, in the village of Shiiba, Miyazaki Prefecture, local authorities said. The man, who runs the construction company, is the husband of the missing woman.

The typhoon is now headed north towards South and North Korea.