30 November 2020
Developing problems at Rest and Be Thankful
In recent months I have posted on a number of occasions about the developing landslide problems at the now infamous Rest and Be Thankful in W Scotland. Unfortunately, the landslides there continue to develop, causing increasing levels of disruption. Last night both the A83 itself and the Old Military Road diversion were closed once again as a precaution. We are in a spell of repeated rainfall events in the area; with the material being so unstable on the slope the roads cannot be safely operated in the dark (and of course the nights are very long in Scotland at this time of the year).
BEAR NW Trunk Roads have been proactive in providing information as to why these road closures are needed. They are aware that these problems are causing substantial disruption. On 25 November they tweeted a drone video of the site above the road that is now causing so much concern:
#A83 #RestAndBeThankful: OMR to remain *CLOSED* overnight & throughout Thursday as a safety precaution with material continuing to move down the hillside. The drone footage below shows the damaged slope above the A83 that resulted from the landslips of earlier this year. (1/2) pic.twitter.com/xjRcKM507n
— BEAR NW Trunk Roads (@NWTrunkRoads) November 25, 2020
This video shows the range of landslide types now active at Rest and Be Thankful. Of particular interest is the landslide in the centre of the video, which is clearly retrogressing and releasing a large volume of debris:-
Note the shallow flow to the left as well, the source of which lies much further up the hillside.
The main landslide highlighted above involves a large volume of material, and it is actively destabilising more. BEAR NW Trunk Roads has also tweeted these time lapse videos showing movement of material in the main landslide during heavy rainfall:-
#A83 #RestAndBeThankful: Here's a clip of our timelapse camera showing the recent debris movement on a loop -teams are monitoring the hillside continuously. All traffic continues to be diverted via A82, A85 & A819 as a safety precaution. Read more: https://t.co/Vln8hfk6JT (2/2) pic.twitter.com/Sapj6OkIno
— BEAR NW Trunk Roads (@NWTrunkRoads) November 24, 2020
The second of these videos shows the full magnitude of the challenges faced by the geotechnical engineers and engineering geologists at this site, and the amount of material that could become involved. Given the terrain, this is not a problem that is going to be fixed anytime soon, although works are underway to try to minimise the impacts.