A massive November 2020 landslide and glacial lake outburst near Bute Inlet in BC created a seismic signal equivalent to a 4.9 magnitude earthquake! On November 28, 2020, at about 6 a.m., approximately 18.5 million cubic meters of rock dropped from a mountain, slid roughly one kilometer, and impacted the lake at the base of a retreating glacier. The resulting glacial lake outburst created a tsunami 100 meters high and unleashed horrendous devastation for 13 miles downstream in Elliot Creek, forever impacting the landscape there. There is an article about the event in The Tyee, an independent online news magazine in BC. The video below has aerial footage of the aftermath of the event, which wasn’t actually located until later in December because of the remote nature of the site. As always, Dave Petley has a nice discussion of the event on the Landslide Blog. Thanks to the GBA where I first heard of this event.
For those of you following the landslide in residential La Jolla California known as the Soledad Mountain Road landslide, it made the news again a couple days ago when a section of the slide re-activated and slid 10-ft down the hill. Doesn’t sound like too big of a deal to me, no additional houses damaged. I’m curious how it related to the shear pins they installed a couple of months ago.
Additionally, the San Diego City Attorney has released a report detailing the sequence of events leading up to the landslide. One interesting note is that the Mayor of San Diego is in hot water with the City Attorney’s office for hiring outside legal council to handle the legal aspects of the landslide. According to the City Attorney’s office, he wasn’t allowed to do that, but so far the City Attorney hasn’t stepped in to force the outside attorney(s) to drop the case saying it would open the City up to even more liability.
Residents of approximately 75 of the 111 homes evacuated after the slide have been allowed back into their homes. The City of San Diego is not wasting any time in determining the cause of the slide. The first of three 100-ft deep exploration shafts was excavated on Friday, and a Forensic Geologist from a firm hired by the City was sent down the hole to observe geology conditions and to locate the actual slip surface. Also, claims of leaking City water and/or sewer pipes prior to the failure have begun to surface. More details in the full post. (Photo by NELVIN CEPEDA / San Diego Union-Tribune)