By Democrat reporter
The Old Military Road diversion towards Inverary in Argyll will close overnight after a forecast for heavy rain.
The route has been used as an alternative to the A83 after a significant landslip at the Rest and Be Thankful on 4 August.
It had already rained heavily in Dumbarton before 10am and about 30-40mm of rain is expected to fall in the area over the next 24 hours.
As a precaution, the OMR will close between 21:00 on Thursday and 09:00 on Friday.
Heavy rain has the potential to impact on the steep channels above and below the A83 carriageway, where loose debris and material landed.
Teams are working on a programme of complex repairs on the A83 carriageway which was damaged following the landslide.
It will be fully assessed on Friday morning ahead of expected reopening. Traffic will be diverted via the standard diversion route of the A83, A82, A85 and A819.
However, it was reported on Sunday that road workers have been verbally abused by motorists facing a 59-mile (93km) diversion.
It follows the closure of the A83 at the Rest and Be Thankful after a landslide on 4 August.
Traffic is normally diverted along a parallel road but that route was also closed on Thursday after heavy rain led to debris on the hillside moving.
Workers at the scene said they were threatened by some frustrated drivers facing a lengthier diversion.
Road operator Bear Scotland said the incidents had been reported to police.
Eddie Ross, of road operator Bear Scotland said: “We have been paying close attention to the forecasts in order to ensure if it is safe or not for us to keep the Old Military Road open for road users given the presence of loose debris in the steep channels on the hillside.
“Heavy rain is developing overnight with particularly heavy rain over the weekends
“We need to put safety of road users first. We’ll continue to monitor the hillside and the conditions in the area and do all we can to open the OMR as soon as we can once the safety assessment following the heavy rain is complete.”
He added: “Argyll remains open for business and as ever we thank the local community and road users for their patience and assure them we’re working hard to get the A83 open as quickly and safely as possible.”