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About landslides

Scotland's scenery of high mountains and steep valleys can be prone to landslides under periods of extended heavy rainfall. Read about how we work to manage the impact.

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The A85 in Glen Ogle blocked by two debris flows <br> on 18 August 2004. RAF and Royal Navy helicopters <br> are pictured airlifting some of the 57 occupants from <br> the 20 trapped vehicles to safety. (SRNLS Report 2008 <br>Figure 00-00 COVER SRNLS A85)

Managing the impact of landslides

Transport Scotland manages and seeks to reduce the impact of landslides on the trunk road network in several ways:

  • Monitoring slopes prone to landslides
  • Liaison with weather forecasters for weather warnings
  • Landslide patrols
  • Providing travel warnings/information/advice
  • Landslide risk reduction measures

Landslides are natural events and can occur above or adjacent to sections of our trunk roads.

Though we cannot prevent landslides from occurring we can manage the consequences effectively to reduce the impact of landslide on our trunk road network, keeping everybody fully informed.

Scottish Road Network Landslides Study

The implications of landslides on the operation of the road network were brought into sharp focus in August 2004, when very heavy rainfall led to several road closures in the north and west of Scotland.

Following these events a program of detailed research, began - The Scottish Road Network Landslides Study.

The initial study was published in 2005, followed in 2009 by an Implementation Report however research in relation to landslides is continuing.

The study provides a picture of the potential future risk of landslides in Scotland that may impact on the trunk road network and evidence to help us plan and manage the risk. This helps us to reduce the risk of landslides’ impacting on our trunk roads and road user’s journeys.

Read the reports: 

Scottish Road Network Landslides Study Report (2005)

Scottish Road Network Landslides Study – Implementation Report (2008)

What are landslides?

Debris flow on the A83 Rest and be Thankful on 28 <br>October 2007. © Dr M G Winter by permissionA landslide is defined as a movement of a mass of rock, earth or debris down a slope. Landslides can be divided into the following types of movement: falls, topples, slides and flows.  The type of material involved in the movement can include rock, debris or earth.

The events that have impacted on the Scottish Trunk Road Network in recent years including those at the A83 Rest and be Thankful and A85 Glen Ogle broadly conform to the relatively fast moving, shallow debris-flow type of landslide.  Read more about some further examples of the different types of movement below.

Falls

  • A82 Loch Ness 
  • Altsigh

Slides

Flows 

The weather has a significant influence on landslides which is why we carefully monitor local weather warnings. The debris flow landslides such as those at the Rest and be Thankful are most likely to occur during and immediately after periods of very heavy rainfall, especially if the heavy rain follows an extended rainy period.

Further information

Further general information on landslides can be found on the websites of the British Geological Survey and Scottish Natural Heritage.

Guidance for road users

Safety for all road users is a priority of Transport Scotland.

Safe travel planning tips

Transport Scotland's aim is to keep roads open as safe as possible.

Drivers can help make their trip even safer by following these steps:

  • Plan your journey in advance using the Traffic Scotland website
  • Check the weather forecast before you set off
  • Allow extra travel time
  • Be alert for water or debris on the road
  • Listen for travel bulletins and looking for roadside messages displayed on Variable Message signs
  • Avoid stopping on bridges or next to water courses in mountainous areas
  • Plan your stops in towns and villages rather than the open roadside

Road signs

Sign indicating risk of landslidesThis sign is typically used to indicate landslides in the United Kingdom.

The definition in the Department for Transport Traffic Signs Manual for this sign is ‘Risk of falling or fallen rocks’.

This sign is used to warn for all types of landslides including debris flows, not just rockfalls.

These signs are used at locations along the trunk road network that have been identified as being susceptible to landslides.

At the A83 at Rest and Be Thankful we have instigated the first ever use of landslide ‘Wig Wag' road signs.

The signs warn road users when there is an increased risk of landslides. When there is an increased risk of a landslide, such as extensive rainfall, the sign will flash.

A Wig-Wag signLike all warning signs this does not mean that the road is closed but acts as a warning to road users who must exercise caution when using the road.

If the wig wag signs are flashing, motorists should avoid stopping, particularly on bridges or next to watercourses but instead to proceed with increased caution. Read more about procedures for wig-wag signs.

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