Boulders 'as big as cars' in Rest and Be Thankful landslip
Clear-up work has begun at the A83 Rest and Be Thankful after heavy rain saw thousands of tonnes of debris slide onto the road.
Engineers said about 6,000 tonnes of debris moved across the hill above the A83 and Old Military Road (OMR) at multiple locations on Tuesday.
Car-sized boulders rolled onto the carriageway after 100mm of rain hit the Argyll hills.
The road and the OMR will remain closed overnight into Thursday.
Geotechnical experts carried out safety inspections at first light on Wednesday.
Bear Scotland, which manages the road, said a large landslip around 200m above the carriageway occurred after the heavy rain created a "fan effect" down multiple water channels some of which reached the roadside.
About 1,500 tonnes of debris is thought to have reached the A83, with around 2,000 tonnes of material washed onto the OMR. In total, the landslide is thought to have moved around 6,000 tonnes of material.
One of the landslip mitigation catch-pits, built to prevent landslip material reaching the road, caught around 2,000 tonnes.
A 42-strong team is on site carrying out assessments, managing the traffic and continuing the clear-up operation using 16 different kinds of heavy machinery including excavators, lorries and sweepers.
The area has been plagued by landslips, and £79.2m has been invested in the maintenance of the route since 2007.
In January the road was closed for two days after being covered by 1,300 tonnes of debris.
Argyll and Bute Council has called for a permanent solution to the problem.
Deputy Provost Roddy McCuish was concerned at the danger to drivers.
He said: "What really concerns me this time is there have been reports of large car-sized boulders being brought down the hillside on to the carriageway and there's been safety inspections taking place for some other potential boulders impacted by the landslip and the heavy rain."
Both the A83 and Old Military Road remained closed overnight.
All traffic is currently being diverted via the standard diversion route via the A83, A82, A85 and A819 and that route is also being monitored to check for any issues.
Temporary traffic lights are currently in place on the A82 at Inveruglas after Tuesday's heavy rain affected a retaining wall, causing some damage to the road.
Traffic Scotland are also providing additional advanced warning signs for road users and Western Ferries have also added additional sailings on their usual Gourock to Dunoon route.
Eddie Ross from Bear Scotland said: "Our teams have mobilised at both ends of the A83 at the Rest and OMR and have begun the initial clear-up of the debris.
"Further assessments need to be completed by geotechnical specialists of the hillside and both roads to check for any further concerns, and until these checks and the clear-up is complete the A83 and OMR will remain closed.
"In the meantime, Argyll remains open for business and we encourage road users to follow the diversion route."
In March, Transport Scotland said £1.9m was being invested in the construction of a new catch pit on the hillside to improve the resilience of the vital route.
The mitigation measures also included improved drainage and hillside planting.
Transport Scotland previously said work carried out since 2013 was estimated to have kept the A83 open for at least 48 days when it would otherwise have closed.
This includes the October 2018 event, the largest on record, which prevented approximately 3,200 tonnes of material reaching the A83.
A yellow warning for heavy rain was issued by the Met office for heavy and persistent rain from 06:00 until midnight on Wednesday.
The main areas affected were Mid and North Argyll, Stirlingshire, Lochaber and Southern parts of Skye.
The Scottish Environment Protection Agency (Sepa) warned people to prepare for potential flooding around rivers, and to expect surface water in areas in the west of Scotland.
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Emergency Services were called to the Hillfoots in Clackmannanshire when Tillicoultry Burn burst its banks.
Fire crews helped people evacuate flooded properties in the Hareburn Road area of the town.
In Lochwinnoch, fire crews had to push a car through flood water on the A760 following torrential rain.
Flood water covering the road at Glen Fruin in Helensburgh was also posted on social media.
The heavy rain was expected to ease off overnight.