The A82 Inverness to Glasgow road is currently closed in both directions at Pulpit Rock in Argyll due to a collapsed drain.
Traffic is queuing on both the northbound and southbound carriageways and the disruption is being described as “severe”.
The incident happened at about 4.50pm and the road is expected to remain closed for up to an hour.
A Bear Scotland spokesman said: “We have been advised that the A82 between Tarbet and Crianlarich is presently closed at Pulpit Rock due to the collapse of an old culvert under the road.
“Bear Scotland is currently working with contractors McLaughlin and Harvey to assess the site.”
