Heavy rain forecast for this evening is to force the closure of the diversion route past the landslip plagued Rest and Be Thankful.
The Old Military Road, which was also hindered by last Tuesday’s landslips, reopened on Saturday morning saving motorists from a near 60-mile detour, however, workers have now said it will close from 9pm tonight with a reassessment to take place tomorrow “at first light”.
Clean up bosses have raised concern over the potential for debris to become dislodged during heavy rain and impact the A83 Tarbet to Campbeltown route and Old Military Road.
Eddie Ross, Bear Scotland’s north west representative, said: “Safety is our top priority and following tonight’s forecast heavy rainfall warning from the Met Office and input from our geotechnical specialists we have taken the difficult decision to close the Old Military Road as a precaution overnight tonight.
“The forecast has indicated localised short heavy rain showers which will impact the Rest and Be Thankful, and given the indication of loose material present in the channel high above the road we want to make sure all road users, as well as our own teams, remain safe, and therefore the only option is to close the local road overnight.
“A full safety assessment will take place at first light tomorrow morning to check if any material was dislodged in the channel and to see if the Old Military Road was impacted.
“Once we are satisfied that the route is safe to reopen the local diversion route will be implemented as before.
“The previous standard diversion route via the A83, A82, A85 and A819 will be reinstated from 9pm tonight until it is considered safe to reopen the local Old Military Road diversion route.
“Safety has to come first and as ever we thank the local community and road users for their patience while we address the situation at the Rest.”
Approximately six tonnes of debris fell last week onto the famed spot with boulders the size of cars exposed on the hillside.
Mr Ross added: “Argyll remains very much open for business and we ask road users to plan their journey in advance by checking Traffic Scotland for the real-time travel information.”
Specialist engineers and workers are still assessing the full impact of the landslip with teams drawing up designs to allow engineers to restore the road to a safe condition.
What Happened at the Rest and Be Thankful?
A large landslide occurred on the evening of Tuesday August 4 at the Rest and Be Thankful blocking the road after around 100mm of rain fell in the Argyll area.
The source of the landslip was located around 656 feet high above the A83, which split into two main channels as it spread out in a fan effect down the hillside.
One of the channels filtered into one of the landslip mitigation catch-pits which prevented around 2,000 tonnes of material from reaching the road, with around 1,500 tonnes of debris reaching the carriageway at the second channel.
Car-sized boulders also reached the roadside in the debris.
A further 2,000 tonnes of material was washed onto the Old Military Road.
In total, the landslide is thought to have moved around 6,000 tonnes of debris down the hill, one of the largest landslips in recent times.
On Wednesday August 5 teams began the initial clear-up operations and carried out geotechnical assessments and safety investigations into the damage caused by the landslip.
The flow of debris from the A83 and accompanying water flow from Tuesday’s heavy rain caused significant scouring to the embankment slope below the A83, which undermined the road and demolished the roadside safety barrier.
For safety, the road and Old Military Road remained closed.
On Thursday August 6 a further 100 tonnes of material reached the carriageway overnight via the steep channel scoured out by Tuesday’s landslip, exposing large boulders.
Teams worked to make these boulders safe using water-bags dropped into position from a helicopter as well as using a high-pressured hydraulic ‘jack’ to force the boulders into a new, safer position further down the steep channel.
Teams completed the clear-up of 2,000 tonnes of debris from the Old Military Road on Friday 7 August and have begun work to construct a protective bund and channel parallel to the roadside.
The Old Military Road was opened under convoy operations as a local diversion route on Saturday August 8 at 9:15am, operating 24 hours a day.
Designs are being drawn up to repair the A83 which suffered significant damage in the landslip.
Forecast heavy rain overnight tonight means the Old Military Road is to close at 9pm.
Motorists will instead be diverted via the usual standard diversion route on the A83, A82, A85 and A819.