3 November 2022
Pierreville: an interesting landslide in Quebec, Canada
On 1 November 2022 at about 3:30 am local time an interesting landslide occurred at Pierreville in Quebec, Canada. There is an excellent drone video of the aftermath of the landslide on Youtube:-
I think the location is 46.079, -72.846, although this needs to be confirmed. This image is from the video:-
La Ronge Northerner has an article about the event (with what I take to be a surprising typo, if you can find it!). No-one was killed by the landslide, and the images indicate that the houses have not been damaged so far. A van driving along the road crashed into the landslide, the driver survived but was treated for shock.
The landslide is a slump/spread, with some rotational component. This still from the video shows the rather complex form of the deposit:-
Note the materials involved in the landslide, which are clearly fine-grained.
The timing of the failure is intriguing, as there had been no heavy rainfall and the river does not appear to be high or in flood. There is Google Street View imagery of the site from 2014 which shows a fair amount of cracking and some repairs to the road in the area that failed:-
This is not a smoking gun in isolation however – the cracking and repairs could have alternative explanations.
Geotechnical testing will now be needed to determine whether the houses affected will be safe to occupy in the long term, and to plan the remediation of the site to reopen the road. A key priority will be to identify the likelihood of retrogression of the headscarp.