Strong westerly winds in the morning saw the roads around Perelle and Rocquaine covered in seaweed and stones, with a tractor brought in to clear them.
Bailiwick Law Enforcement shut the road between Perelle Garage to the West Show site.
‘The road is impassable,’ it said at about 8am.
‘Please find an alternative route.’
By lunchtime the closure had been extended.
‘It is now closed between Richmond Kiosk and Pleinmont,’ the emergency services wrote.
‘Strong winds and flooding are making these roads too dangerous to use.’
The island has been battered by westerly winds for several days, which has caused trouble at the harbour. Commodore Goodwill’s sailing on Thursday morning was cancelled and last night’s Clipper sailing was for freight only.
Winds are expected to drop to about a force four today and there should be some sunshine. But today is also the peak of this series of spring tides, with a 9.5m tide just after 7am this morning and a 9.3m tide just before 7.30pm tonight.