The A83 road will be closed until at least Monday after heavy rain caused a landslide at Rest and Be Thankful.
BEAR Scotland say they are unable to conclude safety assessments due to ongoing rain and nature of the landslide.
The road operator say the A83 and Old Military Road will remain closed overnight as a result.
Drivers have been advised to use diversions via A82, A85 and A819.
The extent and source of the landslide will be assessed on Monday and the road will stay closed until it can be considered safe.
A further weather warning for the area will be active from 6pm on Sunday.