A diversion has opened to save drivers a 59-mile trip to avoid a landslip at the Rest and Be Thankful.
More than 1,000 tonnes of material tumbled on to the A83 overnight into Thursday, east of the area covered by debris fences and catchpits.
The A83 has now opened via the Old Military Road, which runs parallel to the affected area, after safety inspections by specialists confirmed it was safe to do so.
The landslip had previously left drivers facing a 58.8-mile alternative route via Crianlarich, Tyndrum, Dalmally and Inveraray in Argyll and Bute.
Traffic will be controlled in a convoy system.
Bear Scotland said its staff are on site assessing the situation on the A83 and will begin clearing the debris when it is safe to do so, in partnership with Forestry and Land Scotland.
Eddie Ross, Bear Scotland’s north-west manager, said: “Safety is our top priority and we’re doing all we can to assess the slope and the extent of the debris from the steep hillside above the carriageway.
“As ever, we thank the local community and road users for their patience, and assure them we’re doing everything we can to address the landslip at the Rest and Be Thankful as quickly and safely as we can.
“We remind road users that Argyll remains open for business and rest assured we’re doing everything possible to ensure the A83 opens as soon as it is safe to do so.”
He advised road users to check Traffic Scotland for the latest information.