Rest and Be Thankful (A83) Landslide, 2011

Rest And Be Thankful location

On 1 December 2011 a new landslide occurred along the A83 Rest and Be Thankful pass (Argyll and Bute, Scotland) which blocked the road. The road was subsequently closed in both directions resulting in a 26 mile diversion. The landslide occurred after 65.8mm of rain, a quarter of the December's expected average for the area, fell in 48 hours.

Following the landslide, the road was fully closed for two days and was then only open during daylight hours for safety reasons from 3 December. The road was fully reopened at 08.30 hours on Tuesday 13 December.

This is the third time that this section of road has been closed in the last five years. The BGS Landslide Response Team surveyed the previous landslides in 2007 and 2009.

The BGS Landslide Response Team made a visit to the landslide on 2 December 2011 to investigate the failure. Information collected from this survey is logged in the BGS National Landslide Database ID 18264/1.

Update: A small landslide (30–50 tonnes) occurred on 22 February 2012, setting off tiltmeter alarms. Although no debris from the landslide reached the road, the A83 was closed for two days as a precaution

News reports

The 2011 landslide was widely reported in the local and national news:

Geology

The geology of the site is described on the 2009 webpage.

Landslide

The landslide is a translational slide that has degraded into a flow as it has passed over a local break of slope, moving approximately 100 tonnes of material. In the lower section of the slope it has exploited a small gully.

This new landslide is approximately 370 metres south-east of the 2007 and 2009 landslides which had exploited a much larger drainage channel.

As with the 2007 and 2009 landslides, this landslide appears to be part of much older landslide features, with numerous tension cracks visible in the slope around the 2011 event.

2011 A83 Rest and Be Thankful landslide.

Eastern slope above the A83 showing the position of the 2007, 2009 and 2011 landslides.

Numerous tension cracks in slope surrounding 2011 landslide.

Lower portion of 2011 slide exploiting a small gully.

Slope above 2011 landslide.

Lower portion of 2011 slide with water emanating from gully.

Contact the Landslide Response Team

British Geological Survey
Keyworth
Nottingham
NG12 5GG
E-mail: Landslides team
Telephone: 0115 936 3143
Fax: 0115 936 3276