A section of the Mountain Road is now closed until Midday, after a wall collapsed.
The DOI says the route between Ramsey and the Bungalow won't be accessible because of the 'hazardous obstruction'.
The closure is due to be in place until 12 - but could be longer as the department says the condition and safety of the road will need to be reviewed.
Meanwhile, access to the Mountain Road from the Tholt-Y-Will is unaffected.
Manxman sailings in doubt from tomorrow
Car falls down steep bank on Mountain Road
Panic over - Mcdonald's reopens at 11am tomorrow
Police say beat it to cars illegally parked during MJ tribute act
No dedicated prostate cancer screening programme, despite over 1,200 referrals
Minister says GP waiting times have improved, but delays still impact A&E
Crash closes section of the Mountain Road
Island's prison nears full capacity