The Rest and be Thankful road will be closed over the weekend due to fresh landslips caused by Storm Callum.
Heavy rain and strong winds brought 300 tonnes of debris from the hillside on to the A83 in Argyll and Bute on Friday as operators tried to clear landslips from earlier in the week.
The closure has caused a diversion of almost 60 miles for motorists but as the weather is not expected to improve until Saturday, Bear Scotland said the A83 will remain closed for the weekend.
Transport Secretary Michael Matheson said: “The landslides at the Rest and Be Thankful this week have been some of the most challenging in recent memory both for the community and for the teams working in difficult conditions.
“I saw for myself this morning the size of the challenge with secondary slips complicating matters and delaying use of the Old Military Road diversion route.
“It is a dynamic situation on the hillside. There are warnings of further heavy rain, and while every effort is being made to get traffic moving, today’s events reinforce the need for a safety-first approach.
“I understand that local residents and businesses are being inconvenienced as a result of these events and I would like to thank them for their patience during the disruption.”
Yellow Met Office warnings are in place for wind and rain in the Highlands and Islands and Strathclyde areas throughout Friday.
Forecasters said that some delays to road, rail, air and ferry transport are likely, as are delays for high-sided vehicles on exposed routes and bridges and some power loss is possible.