City crews were rallying and snow plow engines were revving as a winter storm made its way toward the Toronto area overnight.

City officials expect the blizzard-like conditions descending on southern Ontario through Wednesday to wreak havoc on streets and at airports, as buckets of snow drop on the region.

As much as 30 centimetres of snow is expected to fall on the stretch of Ontario between Windsor and London, as well as Hamilton.

City officials say they are bringing out the big guns to combat what is expected to be difficult driving conditions during Wednesday's morning commute.

Toronto's 600 snow plows, 300 sidewalk plows and 200 salt trucks will be involved in clearing the city's 3,600 kilometres of roads.

Plows and salt trucks will focus on clearing highways and the main arteries as soon as the snow hits, but side streets may not be cleared until Wednesday afternoon or even Thursday.

"The snow is expected to come heaviest overnight," said Myles Currie, Toronto's director of transportation. "Our goal is to have one, maybe two rounds of plowing on the main roads and the expressways so traffic can get through to the core."

A snow melting machine, sitting idle on the Exhibition Place grounds, will also be called into action to dispatch the tones of snow expected to fall overnight.

Plows will cart snow to the fairgrounds and feed it into the machine, which will melt it into water and drop it into the sewer system. The machine can melt hundreds of tonnes of snow per hour.

Regardless of how smoothly the cleaning efforts go, officials warn that morning roads will feature dangerous driving conditions.

Drivers were already dreading the morning commute, maligning what is expected to be treacherous road conditions.

Ontario police are urging motorists to avoid non-essential travel during the storm, and to work from home or take public transit whenever possible. Those who decide to drive should use extra caution on roads and highways.

Beck Taxi, one of Toronto's largest cab companies, was preparing for Wednesday's onslaught. Manager Kristine Hubbard said demand for cabs goes up after a winter wallop.

"It is a blessing and a curse at the same time," Hubbard told CTV Toronto. "We will be very, very busy in our dispatch office but our drivers will have a difficult time getting around on the roads, like everybody else."

At Pearson Airport, 200 flights into storm-ravaged U.S. cities were delayed or cancelled on Tuesday. Airport officials recommend anyone expecting to fly out of Toronto on Wednesday check for delays and give themselves plenty of time at the airport.

Fifty Air Canada flights have already been cancelled on Wednesday, a day expected to be hampered by even more delays and cancellations. Trish Krale, a spokesperson for the Greater Toronto Airport Authority, said crews would be doing their best to keep Pearson International Airport moving.

"Safety is our primary concern in an event like this," Krale told CTV Toronto. "It is all hands on deck. Our snow removal crews will be out there in full force."

School officials are also suggesting parents check the Toronto District School Board website for weather-related closures.

With files from CTV Toronto's Michelle Dube, John Musselman and Naomi Parness