As of 7 p.m., the official total at Philadelphia International Airport was 11 inches, setting two records: the most snow for Jan. 21, and the third snowfall of six inches or more before Feb. 1 - something that had never happened before, according to records dating back to 1884. More than 12 inches of snow were expected by the time the storm ends.
Nutter said all Philadelphia public and parochial schools would be closed Wednesday. City offices and courts also will be closed. And the Archdiocese of Philadelphia said all buses leaving from Philadelphia for Wednesday's March for Life in Washington had been canceled.
Nutter declared Philadelphia's first snow emergency in three years based in part on the accumulation, but, more important, on the forecast of extreme cold.
Come Wednesday morning, he said, "our temperatures will be in the single digits, not rising above the teens all day long. We expect below freezing temperatures through the end of the week, perhaps into the weekend."
Nutter said it would likely take 48 to 72 hours to clear all city streets. "This is going to be a marathon," he said.
Tuesday's evening commute, whether by road or rail, was unforgiving for many. SEPTA trains were running late, service was suspended on a few bus lines, and PATCO activated its snow schedule.
New Jersey state police said that by late afternoon they had responded to 238 motor-vehicle accidents and 354 motorists who needed help. Scores of accidents were reported in Southeastern Pennsylvania.
Along Lancaster Avenue and Martin Luther King Drive, Emily DiTomo was battling snow that was quickly accumulating. She had begun her nine-mile drive from her workplace in Lower Merion to her home in Logan Square around 12:40 p.m. It would not end until nearly 3 p.m.
"It was crazy driving conditions out there," said DiTomo, 37, describing two-lane roads squished to one because of snow banks, near-blizzard conditions, and speeds in her car that rarely seemed to top 5 m.p.h.
Jeffrey Featherstone, a Temple University professor, witnessed the desperation at 30th Street Station as he tried to catch a train home to Wallingford.
He arrived about 2:15 p.m. and waited on the platform, with snow blowing in, while westbound trains zipped by, full.
"We were all standing there, and three trains just went right by us. People were all but hanging out the windows," he said.
Even the conductors had a hard time getting on board.
"They were telling people to move, and they wouldn't," Featherstone said. "It was ugly."
Scuttlebutt was that some people were backtracking, taking trains or the subway back to Market East so they could have a better shot at getting on the train, but Featherstone stuck it out and squeezed on a train and got home at 4:40 p.m.
The scene was more orderly at Market East station, where hundreds of people lined the platforms
About 2:15, Thomas M. Brown Jr., an instructor at Penn State Abington, said he had been at the station for about two hours waiting for a train to Newark, Del.
He lauded the crowd for remaining patient. "You notice that everybody is calm, which is very, very nice. Everybody's cooperating," Brown said.
In Camden County, cars on the road during the day prevented crews from being able to efficiently clear roads, Freeholder Ian K. Leonard said. The problem was exacerbated by the extended duration of the storm, he said, because crews could not simply go through and plow roads once or twice.
"Bottom line is, you've got 400 miles of road to cover, and you have an intense storm that's going to go probably another 12 or 16 hours," Leonard said. "It's a challenge to fight that and try to get ahead of it."
Leonard could not guarantee a clear morning commute for all. "You've got a storm like this, it's not going to stop. It's going to continue to go all night," he said. All the crews can do is "just keep plowing."
At Philadelphia International Airport, hundreds of flights were canceled. One runway was open, so the airport was operating, though there were "very few people" in the terminals, spokeswoman Victoria Lupica said.
Flights were taking from 90 to 100 minutes to get airborne with de-icing, slow taxis, and snow removal, Lupica said. Later in the day, airlines began winding down operations and preparing to get back to normal Wednesday.
By early evening, the normally congested streets of Center City and elsewhere were largely empty as the region hunkered down to get ready for Wednesday's cleanup.
The Carolina Hurricanes were in town to face the Flyers, but the game was postponed because of the storm.
The winter storm formed along a stalled arctic boundary, drawing strength from temperature contrasts and gathering moisture as it approached the Atlantic Coast off North Carolina.
Although temperatures were uniformly low and snowfall widespread, snow totals varied dramatically, more typical of a March storm when temperatures are within a few degrees of freezing. But, as it did in the region's first two significant storms this season, the snow showed a particular preference for areas in and around Philadelphia.
At midday, a profoundly heavy snow band developed over the I-95 and I-295 corridors, with snow accumulating at rates of up to two inches an hour, according to the National Weather Service.
With so much of the energy focused on that band, said Dave Dombek, a meteorologist with AccuWeather Inc., snowfall was considerably lighter elsewhere, and almost nothing fell at the Shore during the day.
The city has weathered storms with larger snowfalls in recent years without declaring a snow emergency. But this one was different, Nutter said, because of its intensity.
"This is going to be very rough," the mayor said.
Nutter asked residents to check on senior citizens and shut-ins in their communities and to help with keep their steps and sidewalks cleared of snow.
At least one Tastykake deliveryman would not let the snow stop him from making his rounds.
Chuck Priestley, 62, of Havertown, began work at 2 a.m., an hour earlier than usual, then gingerly negotiated his route from City Avenue and 54th Street out to Villanova. His first stop was the company's Navy Yard headquarters in South Philadelphia to load his blue-and-white panel truck with assorted Krimpets, Chocolate Juniors, and fruit pies.
"If they're baking cake," said the 33-year veteran of snack delivery, "we should be able to serve it."
Contributing to this article were Inquirer staff writers Michael Matza, Carolyn Davis, Kathy Boccella, Mari A. Schaefer, Barbara Boyer, Susan Snyder, Sulaiman Abdur-Rahman, Linda Loyd, Vernon Clark, Michael Vitez, Troy Graham, Marie McCullough, Angela Couloumbis, Jessica Parks, Jeff Gammage, Paul Nussbaum, Chris Palmer, and Bob Warner.