18 December 2018
Loch Quoich landslide: an interesting and disruptive failure in the Highlands of Scotland
Posted by Dave Petley
Loch Quoich landslide: an interesting and disruptive failure in the Highlands of Scotland
On 10th November a significant landslide occurred at Loch Quoich near Kinloch Hourn in the Highlands of western Scotland. The Highland Council has a really good update on this landslide on their webpages, which includes this image:-
The landslide at Loch Quoich in the Highlands of Scotland. Image via the Highland Council.
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This landslide, which has a reported mass of about 9,000 tonnes, extends over a distance of about 1 m. The slip has blocked the road across the slope and also caused operations at the dam to be shut down as a result of debris accumulation in the spillway. The landslide destroyed a pylon, cutting the electricity supply to 20,000 homes, as well as destroying telephone cables. Services have now been restored, but the road remains closed and will not reopen prior to mid 2019.
The best images of the landslide can be found in a drone video that has been posted online to Vimeo by the power company SSEN. The quality of the imagery is fantastic. You may or may not be able to view it below; if not then follow this link:
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This video gives an amazing view of the structure of the landslide. So, starting from the top, this is the source area:-
The source area of the Loch Quoich landslide in Scotland. Still from a drone video posted by SSEN.
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The landslide appears to have initiated through a toppling failure of the rock bluff. Note the very obvious fault running through the middle of the outcrop. The initial failure has entrained a large volume of material from the upper part of the slope to generate a substantial failure. The upper portion of this entrainment zone can be seen below:
The entrainment zone of the Loch Quoich landslide in Scotland. Still from a drone video posted by SSEN.
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Further down the slope the mechanism changes to deposition (with some erosion in the channels):-
The transition from the entrainment zone to the deposition of the Loch Quoich landslide in Scotland. Still from a drone video posted by SSEN.
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Below this the landslide has deposited a comparatively thin mass over a large area. Note the destroyed pylon. It is interesting that the deposit was able to cross the spillway:-
The lower part of the of the Loch Quoich landslide in Scotland. Still from a drone video posted by SSEN.
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Dave Petley is the Vice-Chancellor of the University of Hull in the United Kingdom. His blog provides commentary and analysis of landslide events occurring worldwide, including the landslides themselves, latest research, and conferences and meetings.
Thank Dave! really interesting UK landslide example. Shows how much these splosh out of channels and can ‘ride’ across depresions (spill way).
Looks like the road gave the slide debris a good lift. It would be interesting to estimate its velocity as it leaped across/over the spillway structure.
a good example of a deforested slope. There is a move afoot to regenerate the long-gone forests of the UK
This landslide is not related to deforestation
Any idea when the road will be passible.
Hi there is there possibility road will be passible mid april
Any updates on when the road will be reopened.
Andy
Just been down the road as far as Kingie, small hamlet above the power station below the dam, a gate has been put across the road preventing access and locals are talking about up to six months before it will be open.
It was opened to public on 18 April. http://www.kinlochhourn.com/ Drove over it on Wednesday. Plenty of work still to be done. Road has temporary surface but is perfectly passable.
Just looking at this mass movement properly for the first time in an idle hour and I notice that the source zone for the initial failure was the outcrop marked as having a cave (at 069030) on both the 1:50,000 and 1:25,000 OS maps. I remember climbing up the adjacent hillslope on the (true) left bank of the Allt Garuidhe in August, 2014 (en route to the summit of Spidean Mialach) but failing to notice the cave – but it can just be detected on the current air photos in the Bing mapping package (https://www.bing.com/maps).