Dozens of flights have been cancelled and transportation officials have shut down a 170-kilometre stretch of the Trans-Canada Highway in New Brunswick and Nova Scotia as a blizzard wreaked havoc on travel across nearly every county in the Maritimes.

Snow started in the Halifax region just after 5 a.m. AT, and strong winds continue to build in the region.

Many schools, businesses and city services closed for the day.

Transportation departments in Nova Scotia and New Brunswick closed the Trans-Canada Highway between Moncton, N.B., and Truro, N.S., Tuesday morning. Blowing snow and high winds made the road impassable.

"The Moncton area, Amherst, they are really getting hit hard. They've got about a foot and a half down already," said Barb Baillie, with maintenance and operations for the Nova Scotia Department of Transportation.

"It's been all hands on deck since about 9 o'clock this morning."

Dozens of flights into and out of the Maritimes — at Halifax Stanfield International Airport, as well as airports across New Brunswick and Prince Edward Island — have been delayed or cancelled due to the storm.

Travellers are advised to check the status of their flight before heading out to the airport.

A low pressure system is continuing to intensify as it makes its way from the eastern U.S. up the Atlantic seaboard to the Maritimes. 

Heavy snow over the southwest Maritimes is forecast to spread northeastward over the rest of the region by Tuesday afternoon. 

Strong winds, gusting to 100 km/h or more, will produce blizzard-like conditions with near-zero visibility, Environment Canada warns.

Major storm hammers Maritimes6:57

24 hours of snow, wind

The storm is expected to dump as much as 15 to 30 centimetres of snow throughout the region, though snowfall totals could be higher in some areas.

"Over parts of Nova Scotia and Prince Edward Island, snow will mix with or change to ice pellets and freezing rain later this afternoon, then rain in the evening. Elsewhere the snow will taper off overnight or Wednesday," Environment Canada said.

CBC meteorologist Peter Coade said this storm is slow-moving. 

"This feature will track to the east-northeast to be centred over Yarmouth just after daybreak [Wednesday] morning and then slowly track the length of Nova Scotia to move off the northern tip of Cape Breton by mid-evening Wednesday," he said. 

"This is one of the reasons for the blizzard warnings — the slow motion of the storm centre over the region — maintaining the snow and wind for about 24 hours in New Brunswick and Prince Edward Island."

Coade said the snow should let up Wednesday evening in New Brunswick and P.E.I.

In Nova Scotia, the snow is forecast to change to rain and freezing rain Tuesday afternoon. In Nova Scotia, winds are expected to taper off by Tuesday afternoon, but are forecast to stay strong for the rest of the Maritimes until later Wednesday.

Snowstorm vs. blizzard: What's the difference?

The U.S National Weather Service issued a blizzard warning for a huge swath of the Northeast, from New Jersey to Massachusetts, meaning potential whiteout conditions as heavy snow swirls amid gusting wind

The weather service said a blizzard includes sustained or frequent wind gusts of 56 km/h or greater and considerable falling snow that lasts for at least three hours.

This storm is expected to last up to 36 hours in some locations, forecasters said. But they warn another storm could be looming.