Updated 03/05/13 – 10:20 p.m.

CHICAGO (CBS) — Snow plows were out in force, hundreds of flights have been cancelled at the city’s airports, and many area schools were closed on Tuesday, amid a storm that could drop up to 10 inches of snow.

Some area snow totals: 7.7 inches at O’Hare, 7.4 in Joliet, 6.6 in Schereville, 6.5 in Morton Grove and 6.0 in Hyde Park.

RELATED: Massive Flight Cancellations At O’Hare, Midway

Even before the snow started falling, airlines were cancelling hundreds of flights at O’Hare International Airport and Midway International Airport.

As of 5 p.m., more than 900 flights had been cancelled at O’Hare; and more than 240 had been cancelled at Midway.

Forecasters were predicting as much as 10 inches of snow in some spots by the time the storm is over, though most areas will see between 4 and 8 inches.

Light flurries began to fall around 6 a.m. in the western suburbs, and by mid-morning, it was snowing steadily in Chicago.

The snow was falling fast and heavy in some areas Monday afternoon. In Streator, about 100 miles southwest of downtown Chicago, 4 inches had been reported by 10 a.m., while 2.1 inches had been reported in northwest suburban Arlington Heights at the same time.

CBS 2’s Susanna Song reports plows have been out salting area roads since early Tuesday, in anticipation of the heaviest single snowfall of the season..

The Chicago Department of Streets and Sanitation deployed its full fleet of 284 plows around 2:30 a.m. Those plows will focus first on the city’s main streets and Lake Shore Drive, then move to residential streets later.

The Illinois Department of Transportation said it has nearly 600 trucks throughout the state working to keep interstates and state highways clear of snow and ice.

The Illinois Tollway also deployed its full fleet of 182 plows to patrol the Chicago area toll roads.

Those plows have been salting throughout the early morning hours to make sure, when the snow does fall, pre-treated roads will have fewer slick spots, because they have already been salted.

While the morning rush hour wasn’t significantly affected by the light snowfall so far, the afternoon rush could be a big mess for commuters.

“We’re expecting a lot of snow, a lot of wet snow on the ground. Driving conditions could be very challenging,” IDOT spokesman Mike Claffey said. “We’re advising folks don’t drive, unless you have to.”

Officials also warned drivers not to try to pass snow plows on the roads, and give them plenty of room to operate. Last week, dozens of accidents happened when motorists tried to pass plows.

“Allow the trucks to do their jobs. Just last week, we had a number of plows get in crashes with vehicles trying to pass them,” Claffey said. “The plow drivers do not have good visibility around them, so we want to just watch out for the plows, let them do their job.”

Naperville resident Ayesha Hasan was happy to see more snow.

“It’s great, actually. I’m loving it,” she said. “I have my three boys to work for me, to shovel the snow.”

Many local schools and universities have cancelled classes for the day, or were closing early on Tuesday, in anticipation of the heavy snowfall. You can check a full list of Chicago area school closings here.

Naperville teacher Steve Gee was among thousands of teachers spending the day at home, because of school closings.

“We’ll see if the big storm really comes,” he said. “I always am skeptical. You know, you never know if it really is going to hit or not.”

Watch & Listen LIVE