Efforts are under way to clear the A83 at the Rest and Be Thankful in Argyll after a landslide brought a torrent of mud down the hillside onto the road.
The road has been closed since lunchtime on Tuesday when 600 tonnes of mud and rubble were swept down after sustained heavy rain.
Westbound traffic is currently being diverted at Arrochar with eastbound traffic diverted at Inverary.
A landslide closed the road at almost exactly the same spot in October 2007.
We'll be going up onto the slope to assess the stability of the material that remains up above the road and also the embankment supporting the road
Martin Spicer Transerv
Forecasters said Argyll had now seen the worst of the wet weather, with 59mm (2.3in) falling at Tyndrum in the 24 hours up until 1400 BST.
Lorries working late into Tuesday night and early on Wednesday morning had cleared about two-thirds of the debris from the 100m stretch of the A83.
Although only a small section of road was affected, the detours have added an extra 60 miles to journeys.
Road contractor Transerv's Martin Spicer told BBC Radio Scotland's Good Morning Scotland programme that good progress had been made in clearing the slip.
He said: "We've got another 100 to 200 tonnes of material to shift and we've got a fleet of wagons to do that.
Experts will be assessing the safety of the road before it reopens
"Later today, as the conditions continue to improve, we'll be going up onto the slope to assess the stability of the material that remains up above the road, and also the embankment supporting the road, before we can make any kind of assessment as to when it can reopen."
Mr Spicer said the potential of a slip had been identified during the period of sustained bad weather, and traffic lights on the stretch had been switched to red to prevent any danger to road users.
Kris Clark, proprietor of the George Hotel in Inverary, said the blocked road was again costing money and affecting business, and longer-term improvements were needed.
He said: "I suppose it comes down to funding doesn't it, it's a money issue. It's a huge undertaking financially and population-wise I suppose we're not considered to be the most populated area. Is it a question of lack of funding due to that?
"If this had happened outside Glasgow you can guarantee this would be resolved within a year or so - they'd build a structure like you see on the continent that would ensure this would never happen again."
Environment Minister Roseanna Cunningham said the Rest and Be Thankful was a key part of the road network in the west of Scotland and as an MSP who represents a rural constituency, she sympathised with local residents .
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