A winter storm that blew into southwestern Ontario early Wednesday from the United States was expected to cause a variety of travel headaches Thursday.

Environment Canada posted winter storm warnings late Wednesday for Ontario`s Niagara region, eastern Ontario, southern Quebec and much of northern New Brunswick.

Toronto has already received 10 centimetres of snow, but the good news is  the GTA will be dealing with only flurries by mid-morning on Thursday.  By 4 o'clock this morning, over 600 plows have been out on area highways and city streets. It'll be a great opportunity for the kids to go tobogganing. Here are some of the best hills to check out.

Some of the hardest hit areas in Ontario, are the Niagara and Hamilton areas. Residents there could be clearing their driveways of 15 to 20 centimetres of the white stuff.  Environment Canada says the Montreal region could receive up to 30 centimetres of snow accompanied by widespread blowing snow.

In New Brunswick, snow and blowing snow was expected to begin early Thursday in the southwest and eastern regions, with about 25 centimetres or more expected.

Hundreds of flights were cancelled or delayed out of U.S. airports and several departures had been cancelled by early Thursday at Pearson International Airport in Toronto and at Montreal's Trudeau Airport. Travellers were urged to call ahead to check on their flight status before heading to the airports.

To check your flight status out of Pearson International, click here.

The storm had already pounded the midsection of the U.S., dumping a record snowfall in Arkansas and lashing the Northeast with high winds, snow and sleet. Those stormy conditions are blamed for at least six deaths in the U.S., knocked out power to thousands of utility customers, primarily in Arkansas.
   
(Some files by AP)