Most of southern Ontario remained under a winter storm warning by Environment Canada as heavy snow began to pummel the region for the second time in less than 24 hours.

Commuters in the Greater Toronto Area got through the morning rush hour by driving through more than 10 centimetres of wet snow Wednesday morning.

Forecasters predicted another 15 centimetres would start falling at about 4 p.m., just in time for the evening traffic rush. The snow is expected to continue to fall throughout the night.

"This storm has the potential to produce snowfall rates as high as 5 centimetres per hour with near zero visibilities especially during the evening hours," says a warning posted on the Environment Canada website.

"The highest snowfall from this system is expected to fall over the Goderich to Palmerston to Orangeville to Newmarket areas tonight with upwards of 20 to 30 centimetres possible there by Thursday morning," the warning continues.

Though city work crews took advantage of a break in the storm Wednesday afternoon to clear the roads after the morning storm, there is still expected to be havoc on the roads throughout the evening as the snow intensifies.

According to the Ontario Provincial Police, there were "hundreds" of accidents reported throughout the day. During the morning traffic rush, police reported about one crash every two minutes as commuters tried to make their way through slippery conditions and poor visibility on the roads.

"Some people are trying to do the speed limit out there, and we have ice and slush and snow," OPP Sgt. Cam Woolley told CTV Toronto. "Conditions are less than ideal -- and of course the speed limit is set for ideal conditions."

Bus, flight cancellation

Travellers waiting for flights at Pearson International Airport were faced with numerous delays and cancellations.

About 100 flights were cancelled and another 20 delayed Wednesday morning.

Airport officials warned travellers to call ahead to check on their flight status before heading out.

Around the GTA school boards urged parents to keep their children at home during the storm.

Several boards cancelled transportation services.

The Toronto District School Board and Toronto Catholic District School Board have told their school bus drivers to stay home today.

Schools are closed in the Dufferin-Peel Catholic District School Board and Peel District School board west of Toronto.

Buses were also cancelled in:

  • Clarington;
  • Halton;
  • Peterborough County;
  • Northumberland County;
  • Prince Edward Country;
  • South and Central Hastings;
  • Belleville;
  • Quinte West and
  • Kawartha Lakes

Tomorrow morning, parents can check on school closures by logging on to CTV's school bus monitor site.

Clean streets

Toronto city crews managed to clear off highways and the main arterial roads by late morning but many side streets were still covered with snow by the time the second snowstorm hit.

Peter Noehammer, director of the city's transportation services, said when there are two storms in one day, the city tries to spread out their resources to make sure they have enough to last throughout the system.

He said residents have to do their part to help the city clean up the streets in a timely fashion.

"This is a narrow street and the plow has trouble going around the corner but also going around the parked car so he's trying to plow away from car off the side," he said, speaking to CTV Toronto while following a snow plow.

"He's got to be careful not to do damage to parked cars," he said.

He said it will take about 20 hours before all the streets are cleared.

Here is what you can do to help snow plows:

  • Don't park on the street
  • Don't shovel snow back onto the street
  • Be patient

Residents are reminded they must clear the sidewalk in front of their homes within 12 hours of the snowfall or face a fine of $120

Big business

Most people tried to do their part by clearing off their properties and the sidewalks in front of their homes but the wet snow made it an arduous job.

"Its great having a parking space for three cars in the summer in the winter, no, it's horrible, I hate it," said one woman.

One chiropractor said his clinic sees a spike in calls after a big storm.

"It's heavy snow today, its wet, so its harder to push then of course the lifting techniques play a role," said Dr. Wade Whitten.

Others prefer to pay someone who has heavy equipment to do the heavy lifting.

Tow truck drivers were also kept busy today helping pull cars out of snow banks and towing them away after nasty crashes.

"It never ceases to amaze me what some people get themselves into," said driver Dave Martino.

Abrams Towing Services said they expect to receive about 1300 calls, keeping their staff of 160 drivers fairly busy throughout the day.

"Just like all the other pedestrians and motorists we get stuck just like them -- so we have to be careful not go to areas where we get stuck," said Warren Campbell, operations manager at Abrams.

One woman said it's not a job she would ever want.

"What a horrible job," she said. "I wouldn't want their job for all the tea in China."

With reports from CTV Toronto's Austin Delaney, Naomi Parness and John Musselman