The winter wallop expected to pummel Toronto overnight may only have hit at half strength, but the battery of laughter and derision fired by the rest of Canada more than made up for it Wednesday afternoon.

What had been pegged "Snowmageddon" on online message boards was downgraded to "snow big deal," despite forcing the cancellation of hundreds of flights out of Toronto's Pearson International Airport and prompting local school officials to cancel classes for the first time since 1999.

It didn't help Toronto's snow cred; 1999 was the year former mayor Mel Lastman enlisted the military to help clear city streets, an overreaction rarely overlooked in Western Canada.

"Don't count on the army to help you; they'll be busy in Toronto," one commenter posted on an online news story.

"What a bunch of babies! Come to Edmonton and see what winter is really like," posted another.

Environment Canada downgraded their predictions for Toronto on Wednesday, stepping away from calls for "near blizzard" conditions and up to 30 centimetres of snowfall.

Between 13 and 17 centimetres of snow fell on the city by Wednesday evening.

The storm was still enough to snarl traffic and cause hundreds of flight cancellations in southern Ontario.

The system, which made its way north from Texas on Tuesday and overnight, began dumping snow on the region early Wednesday morning.

Roads quickly became hazardous Wednesday morning and commuters were warned that all unnecessary travel should be avoided.

Sgt. Dave Woodford, of the Ontario Provincial Police, warned Wednesday morning that conditions were universally bad on roads from the Niagara region right through to Barrie, Ont.

"There are no good areas," Woodford said, noting that a number of vehicles have slid off the slippery roads and the situation will likely get worse as people try to get to work.

At Toronto's Pearson International Airport, 340 of the 1,200 scheduled flights were cancelled by Wednesday afternoon.

Scott Armstrong, a spokesperson for the Greater Toronto Airport Authority, said most travellers called ahead before driving to the airport.

However some international travellers were caught unaware.

"It's quite a big surprise to me to end up in this kind of weather because I wasn't expecting it and no one told me before," said Constanze Hettlage, 35, of Germany, after spending the night at the airport.

In the hard-hit London area some secondary roads were drifted in and virtually impassable, while others were closed altogether, Woodford said.

Environment Canada's senior climatologist Dave Phillips said the storm will affect a massive area before it is finished.

"One hundred million people are going to be affected by this storm. From New Mexico to New England from Windsor, Ont. to Windsor, N.L. and Labrador we're talking about this blizzard," he said.

The centre of the storm was expected to move to New York by the afternoon and Cape Cod by evening, Phillips said.

In Canada, he said the storm will move to eastern Ontario and Quebec, then New Brunswick, Nova Scotia and Newfoundland will all be "pummelled by this particular event."