City officials are warning residents there could be major delays on area roads Wednesday as the first major snow storm of the season makes its way into western Quebec and eastern Ontario.

At least 30 centimetres of snow dropped in Pennsylvania and New York Tuesday. By 6 p.m., the storm was already causing some cancellations of U.S. flights scheduled to arrive at the Macdonald-Cartier International Airport in Ottawa.

The storm, which originated in North Carolina, is expected to rapidly intensify, pummeling the region Tuesday night.

"Not a great night for travel at all because blowing snow will reduce visibility . . . A lot of the highways in the region are going to be affected by this," said CTV Ottawa weather specialist J.J. Clarke.

"A bulk of the rotten weather will be happening form about 10 o'clock tonight right through until about 6 o'clock tomorrow morning."

Areas currently under a winter storm warning include: Brockville, Leeds and Grenville, Ottawa, Gatineau, Morrisburg, Long Sault, Winchester, Newington, Smiths Falls, Perth and eastern Lanark County, Prescott, Russell, Cornwall, Lancaster, Maxville and Alexandria.

Areas near the capital are forecasted to receive more than 15 centimetres of snow before the storm tapers off Wednesday.

Clarke says because many of the trees still have leaves on them, residents should also be aware of the increased risk of broken branches that could down power lines in many areas.

Meanwhile, City of Ottawa officials say 75 per cent of its fleet is mobilizing to tackle the winter storm. Some vehicles, however, are unavailable for the early start to winter.

"We have everything we can get our hands on. Some of our equipment is still tied up in summer operations. Some of our contractors are still doing construction but a lot of them have committed to give us a hand, so we are in pretty good shape," said Dan O'Keefe, Ottawa road maintenance manager.

Residents looking for snow tires and shovels were also out of luck at many retail outlets across the capital on Tuesday.

"People first thing this morning started rushing in buying two or three shovels at a time. They heard the news last night that snow is coming so we decided to get some shovels out today," Canadian Tire manager Bob Starmans told CTV Ottawa.

Last year, the first major snowfall hit the area on Nov. 16. The winter of 2007-08 was one of snowiest in recent memory, with snowfall levels approaching the 1970-71 record of 441.1 centimetres.

Despite the snowfall, sidewalks and front porches are expected to be all clear for trick-or-treaters on Halloween night as sunny sky and warm temperatures are forecasted for the region on Thursday and Friday.

With a report from CTV Ottawa's Kate Eggins