Hundreds of airline flights were canceled Saturday and fleets of road plows were warmed up as a paralyzing snowstorm barreled out of the Midwest and spread across the Northeast with a potential for up to 20 inches of snow driven by 50 mph wind.

Storm warnings were posted from Wisconsin to New England, where the National Weather Service (search) posted blizzard warnings in effect through Sunday. By afternoon, snow was falling across a region stretching from Wisconsin and Illinois to Virginia and the New England states.

One man died after falling through ice on a pond in Ohio, where two others died of apparent heart attacks while removing snow, authorities said.

Temperatures in Maine fell to 36 below zero at Masardis, and Bangor (search) dropped to a record low of 29 below. Meteorologists predicted wind up to 50 mph would push wind chill readings to 8 below zero in New York and New Jersey.

In New York, residents were advised to keep their cars off the road for the weekend as snow removers tried to clear 6,300 miles of roadway. Nearly 7 inches of snow had fallen in Central Park by Saturday evening. Almost 9 inches were reported on the eastern tip of Long Island, the National Weather Service said.

The snow wasn't a problem for 29-year-old college student Maya Tudor.

"I like the snow. It slows down the city and blankets a lot of the unpleasantness," she said. "You never see New York this calm. It's an event."

Many people rushed out to stock up on supplies to ride out the storm at home.

"I got a couple steaks, a couple jugs of wine and a couple good books," Walter Trogdash said as he left a convenience store in Toms River, N.J. "I think I'm all set."

North of New York City in Mamaroneck, shoppers stripped the shelves at a Super Stop&Shop of soda, meat, potatoes and beer and the checkout line stretched the length of the store.

"It's awesome," store manager Louis Spinola said of the mob scene.

Up to a foot of snow had fallen in Wisconsin and Michigan, and wind gusted to more than 60 mph across Iowa. As much as 18 inches of snow was forecast in northern New Jersey and accumulations of up to 20 inches were possible in parts of New England and the New York City area, the weather service said. A foot was likely in northern sections of Ohio and Pennsylvania.

While crews in the Midwest labored to remove what already had fallen, highway departments in the Northeast readied hundreds of plows and salt-spreading trucks. New York City canceled all vacations for its sanitation workers and called people in on their days off to handle the snow. Kennedy International Airport had machines capable of melting 500 tons of snow an hour.

If 20 inches of snow fell in New York, the cost of cleanup could hit $20 million, but Mayor Michael Bloomberg (search) said that was a problem for another day.

"The first thing is we're going to take care of the city," Bloomberg said. "And then Monday morning, I'll have to worry about how to pay for it."

"This is our Super Bowl. It's the public servants versus the elements, and we hope to win," said Philadelphia Managing Director Phil Goldsmith.

The blowing snow caused frustrating delays as airlines called off flights.

About 400 flights were canceled Saturday at Chicago's O'Hare International Airport (search) and dozens more were called off at the city's Midway Airport. More than 200 people stayed the night at the two airports because of flights canceled the night before.

Even more chain-reaction cancellations were expected at Chicago and elsewhere as the storm clamped down on airports on the East Coast, said Chicago Department of Aviation spokeswoman Annette Martinez.

The New York metropolitan area's Kennedy and Newark airports had dozens of cancellations as the storm arrived Saturday afternoon, said Port Authority spokesman Alan Hicks. LaGuardia had nearly 200 cancellations by 2 p.m.

By noon at Philadelphia International Airport, the storm had already wiped out about 25 percent of the normal load of 1,100 daily arrivals and departures. A private jet and a commuter plane slid off a taxiway at Pittsburgh International Airport; no one was injured.

At Pittsburgh International Airport, two airplanes slid off a taxiway while trying to take off Saturday morning. Airport officials said no one on the private jet or the commuter plane was injured.

Hundreds of workers at the football stadiums in Pittsburgh and Philadelphia cleaned snow off tarps covering the fields in preparation for the National Football League conference title games that would be held in each city Sunday.

On the highways, Pennsylvania State Police reported dozens of accidents, including one involving 11 cars. New Jersey banned tractor-trailer rigs and motorcycles from the New Jersey Turnpike and slashed the speed limit to 45 mph.

Amtrak said there were minimal delays for its trains Saturday in the Northeast corridor, but it would have a reduced schedule between Washington and Boston and in upstate New York on Sunday.

Detroit delayed the opening of its first annual Motown Winter Blast (search) for several hours to give road crews a chance to clear highways. SAT tests for prospective college students were canceled in Maryland, and several college basketball games were postponed in New Jersey.