The first big storm of the season burdened the metropolitan area with up to 9 inches of snow today, forcing airlines to cancel more than 1,100 flights and making travel miserable on highways and sidewalks.

A winter storm warning was canceled at midafternoon, as the snow changed to rain in the city, but sleet and freezing rain were predicted for overnight.

Mayor Bloomberg said that his army of 2,000 snowfighters was expecting as much as 10 inches by tomorrow morning — and that it would cost $1 million an inch to clear away.

The storm’s impact was felt far from New York, as airports around the country were hamstrung by canceled incoming flights.

“There are no weather problems in Kansas City today, but if that plane from New York to Kansas City is five hours late, then that flight out of Kansas City has no plane,” an AccuWeather meteorologist, Tom Kines, said.

By midafternoon today more than 1,100 flights had been canceled at the region’s three airports, including nearly 550 at LaGuardia Airport alone, Port Authority of New York and New Jersey spokesman Steve Coleman said. Flights were delayed up to three hours at LaGuardia and up to 21⁄2 hours at John F. Kennedy International Airport and Newark Liberty International Airport, he said.

The National Weather Service measured 6 inches in Central Park by noon, when the storm was still going strong. Staten Island, Floral Park, and Croton-on-Hudson had 8 inches and Stratford, Conn., had 9.

Times Square was a mess of gray slush by afternoon, but that didn’t matter to Sydney Cooper of Kingsport, Tenn.

“It’s great,” Mr. Cooper said. “We don’t get snow in Tennessee, so I prayed for it. I was supposed to leave this morning but my flight got canceled.”

A fashion designer from Brooklyn, Mark Mathebane, was taking it less in stride.

“I hate the snow,” he said. “It dirties your shoes, especially when they throw salt on the ground. Salt destroys leather.”

Mr. Bloomberg found a silver lining in the snow clouds — the storm came on a Friday, allowing for a weekend cleanup — and suggested New Yorkers enjoy free hot chocolate and sledding in the parks. But he also warned that tonight’s commute could be dangerous.

“Please, please, please, even if it looks clear, wear your seat belt, drive slowly,” he implored. A winter weather advisory was in effect until 1 a.m. Saturday.

The storm caused countless accidents in the region, including jackknifed tractor-trailers on Interstate 95 in Greenwich, Conn., and an overturned oil tanker on a residential street in Greenburgh. A man was killed in an accident on Interstate 84 in Newtown, Conn.

On Long Island, Paul May said his usual 25-minute morning commute took “a good hour and a half.”

“I didn’t go over 30 mph on the expressway,” he said. “It’s very slippery. The roads are treacherous.”

A Coca-Cola delivery man unloading bottles at a Manhattan convenience store, Anthony Grady, said his normally five-hour route “might take me 10 hours.”

A power outage, possibly weather-related, blacked out 1,600 homes and businesses for about two hours on Staten Island, a Consolidated Edison spokesman, Chris Olert, said.

Many schools in the area were on holiday anyway, but most of the others, from Ohio to Connecticut, were closed by the storm. Aqueduct Raceway canceled its horse races. The Long Island Rail Road City added early afternoon trains to accommodate commuters leaving the city early.

The big storm, which had brought everything from freezing rain to sleet to snow in parts of Kentucky, Missouri, Illinois, and Ohio yesterday, lumbered eastward and northward overnight. Ice on Missouri roads was a factor in accidents that killed five people yesterday and early today, the State Highway Patrol said.

New York City had gone through January with no measurable snow, and the biggest storm before today’s dumped less than 3 inches. But Mr. Kines suggested there might be more ahead, saying, “It’s not a mild weather pattern we’re heading into.”