Flights were cancelled at Toronto's airport on Saturday night, and hydro crews were on standby in New Brunswick, as Eastern Canada braced for a ferocious winter storm.

Environment Canada said the storm could dump up to 25 centimetres of snow on southern Ontario and southern Quebec, while parts of New Brunswick could see as much as 40 centimetres.

The storm, which has already dumped 30 centimetres on Kansas, will inch its way across southwestern Ontario late Saturday, picking up moisture from Lake Ontario as it moves eastward.

Saturday night, Environment Canada placed southern Ontario under a winter storm warning, with snow warnings issued for southern Quebec, New Brunswick and parts of Nova Scotia. A high wind warning was issued for the notoriously blustery Wreckhouse area in southwest Newfoundland.

Prince Edward Island was not under alert Saturday night.

Some of the areas that will be hardest hit in the storm include Hamilton, Burlington, Ont., and Toronto — because of the lake effect — as well as the St. Lawrence Valley and Quebec City, forecasters said. They warned ice pellets could follow after the regions are whacked by snow.

Flights could be cancelled through Monday

Meteorologist Mark Alliksaar said the amount of snow that will fall on southern Ontario on Saturday night and Sunday could be unprecedented for the month of December.

Toronto's Pearson International Airport, Canada's busiest airport, cancelled more than 30 flights Saturday night, mostly flights that were scheduled to leave for the stormy eastern U.S., as well as Montreal and Ottawa.

Air Canada is advising customers to check on the status of all flights, with cancellations expected through to Monday.

Late Saturday afternoon, officials in Toronto said 600 snow plows, 200 salt trucks and 300 sidewalk plows were on standby. Hydro companies also made sure extra staff were on standby in case of any problems with electricity.

Saturday night, the Ontario Provincial Police had extra officers on duty, with others kept on standby to handle any accidents that could arise on the province's highways.

'It will probably be a memorable storm'

The storm is expected to hit New Brunswick Sunday, with the northwestern part of the province expected to get as much as 40 centimetres. A blizzard warning may be issued.

"It will probably be a memorable storm up in northwestern New Brunswick, that's for sure," meteorologist George Parkes of Environment Canada said.

NB Power crews are already on standby.

"We started planning for the storm earlier this week," said spokeswoman Heather MacLean. "We've communicated with other utilities so that we can co-ordinate systems with each other if necessary and we've contracted crews."

Nova Scotia, especially the western half of the province, is expected to get 10 to 15 centimetres on Sunday.

With files from the Canadian Press