HALIFAX -- It is a brutal winter day across much of Atlantic Canada as a significant storm system moves across the region.

The City of St. John's has declared a state of emergency, ordering businesses closed and vehicles off the roads as blizzard conditions descend on the Newfoundland and Labrador capital.

Environment Canada has issued blizzard and wind warnings for much of Newfoundland, with the heaviest snow expected in the Avalon and Bonavista peninsulas, where strong winds and blowing snow may cause whiteout conditions until Saturday.

That same system is battering the Maritimes, where many schools are closed, and some roads are impassable.

Most schools in Nova Scotia are closed, except for those in the Halifax Regional Centre for Education, and some are closed in southeastern New Brunswick.

All public schools in both the French and English school boards are closed.

Several NSCC campuses also decided to close for the day, along with Cape Breton University, the University of Prince Edward Island, and Holland College.

Blowing snow was resulting in whiteout conditions across much of Nova Scotia and Prince Edward Island Friday morning, prompting police to issue warnings about dangerous road conditions due to poor visibility.

It was a dangerous commute for motorists on Nova Scotia’s Highway 102, which was closed between Stewiacke and Shubenacadie for a few hours Friday morning, after a number of vehicles left the road. No injuries were reported.

Blowing snow and whiteout conditions also prompted officials to close the Cobequid Pass in both directions.

The storm is hitting Cape Breton particularly hard. Canada Post has suspended mail delivery on the island for the day, saying weather conditions have made it unsafe for carriers.

Many businesses in the Cape Breton Regional Municipality have closed for the day and several flights in and out of the Sydney airport are cancelled.

Cape Breton Regional Police were asking motorists to avoid unnecessary travel Friday morning, warning that roads were covered in snowdrifts.

CB Transit has cancelled bus service for the day and the Canso Causeway is closed to high-sided vehicles.

Friday’s ferry crossings between North Sydney and Newfoundland have been cancelled and rescheduled until Saturday, though Marine Atlantic says the weather could also affect weekend crossings.

Prince Edward Island is also getting battered by the storm. The RCMP says some sections of roads are impassable and some motorists are abandoning their vehicles after getting stuck in the snow.

All civil service offices on the island are closed for the day, along with some health services.

In addition to blowing snow, the weather system is also bringing frigid cold temperatures to the Maritimes.

Environment Canada has issued extreme cold warnings for communities in northwestern New Brunswick, where temperatures could reach -40 C with the wind chill.

Winter storm warnings are in effect for most of Cape Breton, while special weather statements and blowing snow advisories are in effect for several counties in Nova Scotia. Some communities are also under wind warnings.

Blowing snow advisories are in effect across Prince Edward Island, while Kings County is also under a wind warning.