Gardaí in Donegal have issued a warning tonight that the Knockalla climb towards Rathmullan is treacherous and impassable.
Motorists are advised to avoid the road and take alternative routes.
A garda spokesperson said that Donegal County Council has been notified.
The warning comes ahead of another night of sub-zero temperatures in Donegal. Met Eireann forecasters have said that temperatures could reach as low as -6C and there is a risk of ice and lying snow on untreated surfaces.
Particular care is advised on secondary and local routes, and on higher ground, where ice and frost may linger.
The AA Roadwatch said: Remember it takes up to ten times longer to stop on an icy road. In affected areas, slow down, keep further back from the vehicle in front and keep all manoeuvres gentle.
