A nasty blizzard driven by strong winds is hammering Atlantic Canada for the third time in seven days.

Police in Nova Scotia are urging people to stay off the roads as heavy snow, strong winds and whiteout conditions are making driving extremely dangerous, RCMP Sergeant Darrell Beaton said Sunday.

"The news is not good. The wind, which is responsible for the blizzard conditions, is not expected to move off for another 18 to 24 hours," ATV News meteorologist Peter Coade said.

Wind gusts are currently hitting 80 kilometres per hour. "In some areas, that'll be increasing in the overnight ours to up to 100 km/h and persisting through tomorrow," he said.

While the snow will taper off after midnight in mainland Nova Scotia and southern New Brunswick, it will keep coming down in Cape Breton, he said. 
Environment Canada is now forecasting as much as 60 centimetres of snow for the Halifax area and along coastlines, with inland areas getting about 40 centimetres.

This adds to the snow that already fell on the region in snowstorms on Monday and Thursday.

CTV's John Vennavally-Rao said late Sunday that the Trans-Canada Highway between Nova Scotia and New Brunswick was ordered closed until Monday morning. Earlier in the day, two people were injured in an accident on the highway near Moncton.

Halifax International Airport cancelled all arriving and departing flights until late Sunday.

As he sat at the airport, Terry Connors was resigned to the fact he probably wouldn't be flying to St. John's today.

"Last night they probably knew connecting flights from Halifax were going to be cancelled. It would have been nice knowing before," he told ATV News. "I would have just changed my travel plans altogether."

The system is also pounding southeastern New Brunswick, all of Prince Edward Island and will likely do the same when it heads on to Newfoundland late Monday.

Newfoundland is coping with its own snowstorm. It got 60 cm on Saturday. Conditions got so bad in some places that snow plows were pulled off the road between St. John's and Bonavista.

Toronto's power outage

In Toronto, cold weather was behind a water main's break that caused a power outage in the downtown core.

It was restored around 9 p.m. EST, making for a 14-hour outage. The line broke near a downtown hydro power station around 7 a.m. -- when the temperature was -21 Celsius; a normal overnight low is -9 C -- and leaked into the station's basement.

Condo and apartment dwellers were welcome to gather at Metro Hall, a city building in the downtown area, to get out of the cold.

Major institutions like  the Eaton Centre and Ryerson University had to close for the day. Toronto's Hospital for Sick Children and some other medical institutions were in the blackout zone but stayed open using emergency generators.

One restaurant owner in the affected area told CFTO News that the outage likely cost her between $500 and $700 in damage.

Officials said the outage's impact would have been much greater on a weekday, as it area affected included much of Toronto's financial district.

South of the border

The blizzard conditions along the Atlantic Seaboard in the U.S. led to states of emergency being declared in Massachusetts and Rhode Island.

Another threat to those along the coast line was flooding. The wind blowing off the ocean, the moon was full and the tides were high.

Up to 75 cm of snow fell north of Boston, with lesser amounts falling in neighboring areas. About 30 cm fell when the weather system passed over the Midwest.

Six deaths are linked to the storm: Three in Ohio, two in Wisconsin and one in Pennsylvania.

Some power outages were reported in Massachusetts. Boston's Logan International Airport shut down early Sunday because snowplow crews couldn't keep up with the weather.

The three airports in the New York area saw nearly 500 flights cancelled. Another 70 were cancelled at Philadelphia's airport.

With a report from CTV's John Vennavally-Rao, ATV's Chantelle Jones and files from The Associated Press