23 September 2022
The 17 September 2022 rock avalanche at Lamplugh Glacier in Alaska
It has been a busy few days for rock avalanches in North America. Hot on the heels of the massive landslide at Ecstall River in British Columbia in Canada comes news of another. This event was detected by Matt Haney of the Alaska Volcano Observatory using seismometer data, and quickly narrowed down to a site on Lamplugh Glacier. Dan Shugar (@WaterSHEDLab) of the University of Calgary has tweeted the details – once again do read the full set of tweets to understand this one in detail:-
Planet Labs captured a beautiful image of the site on 18 September 2022, the day after the failure:-
The rock avalanche has a runout distance of about 6 km by my initial calculation. Unlike the landslide at Ecstall River it has not been channelised, and in this case it has run out across ice. Thus, the deposit has a very different morphology. The flow structures at the tow are beautiful, illustrating the spreading of the landslide in the late (low velocity) stage of movement:-
As Dan has pointed out in his tweets, this rock avalanche has in part travelled across the deposit of the even larger 23 June 2016 rock avalanche at the same site (although a different section of the slope collapsed to generate that one). The relationship between the two landslides is captured on the Planet Labs imagery:-
Once again the team that identified this enormous landslide will, I’m sure, produce a detailed analysis of it in due course. I shall look forward to seeing that publication.
The project team outlined above have rapidly undertaken an analysis of this event and have posted the information online. Thanks to them for doing so. The images are from the wonderful people at Planet Labs.
Planet Team (2022). Planet Application Program Interface: In Space for Life on Earth. San Francisco, CA. https://www.planet.com/