22 July 2020
Qingjiang River: an unusual valley-blocking landslide in Hubei Province, China
On 20 July 2020 a very large landslide occurred in the Enshi Tujia and Miao Autonomous Prefecture in Hubei Province, China, blocking the Quinjiang River. The Xinhua report for this event indicates a volume of about 10 million cubic metres. The main valley was blocked and a barrier lake developed, although it has now breached safely.
I cannot find any images of this landslide in the English language media, which is a shame as it is an impressive event. A quick search for Hubei landslide in Chinese (湖北滑坡) yields a number of images on Chinese news sites. This is the best overview of the landslide that I have found:-
This appears to be a large, mobile earthflow type landslide, The nature of the material suggests to me that it is probably a failure in a thick loess deposit, although this needs to be confirmed. The original failure is surprisingly deep-seated and broad, butt appears that there is little or no failure in the underlying bedrock that forms the gorge.
There is a good drone video of the landslide on Youtube. You will need to excuse the corny music (I recommend that you turn the sound off), but it provides a really good sense of the nature of the failure. The blockage on the Quinjiang River had breached at the time of the video:-
Chine continues to undergo extremely heavy and prolonged rainfall, and there is another Yellow rainfall warning in place today for a large swathe of the country. These conditions are likely to set off an increasing number of landslides. The combination of saturation to a deep level (as the Qingjiang River landslide indicates) and high intensity rainfall (the current forecast includes rates of up to 70 mm per hour) is ideal for promoting slope failure.
Quickslide 1: The Skredkallen landslide in Norway
Yesterday, Louise Vick tweeted some nice images of the Skredkallen rock slope failure in Norway. I’d like to visit this one!
This summer I FINALLY have time to write up my project on the Skredkallen #rockslopefailure. The active slope overlies a large old deposit which displays remnants of marine transgressions. This work has been baptism by fire for me in terms of Arctic coastal geomorphology! pic.twitter.com/olVKzB3Did
— Louise Vick (@LandslideLouise) July 21, 2020
Quickslide 2: Continued landslide mayhem in Nepal
Nepal continues to suffer a high level of losses from landslides as abnormally heavy monsoon rainfall affects a large part of the country. Nepal News has a nice summary of the rainfall that is causing these problems. As with China, these issues will become increasing severe as the rain persists.