Analysis of images of the landslide at Loch Quioch in Scotland that cut off power to 17,000 people and blocked the road to Kinloch Hourn on 12 November has suggested that a toppling failure initiated the landslide.
Landslide specialist Dave Petley, who is also pro vice chancellor of research and innovation at University of Sheffield, has said that the landslide appears to have initiated through a toppling failure of the rock bluff.
The landslide was reported to have displaced 9,000t of material and extends over a 1.6km length. The slope failure destroyed telephone cables, an electricity pylon – resulting in the power cut for Scottish and Southern Energy Networks (SSEN) customers in the Isle of Skye and Western Isles – and debris on the dam spillway had led to the operations there being shut down.
Utility services have since been restored but Highland Council has said that the road may remain closed until at least mid-2019.
Following a review of images and drone footage of the landslide site, Petley said that there is a 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,” he said. “Further down the slope the mechanism changes to deposition with some erosion in the channels.
“Below this the landslide has deposited a comparatively thin mass over a large area and it is interesting that the deposit was able to cross the spillway.”