The storm that shut down much of the South slowly rolled into the Northeast late Tuesday, bringing "very heavy" falls of snow, officials said.
Storm warnings were in effect for most of southern and eastern New England.
In the South, the weather left roads so icy that some truck drivers were stuck for more than a day in their rigs.
Airports in the Northeast, South and even Midwest saw several thousand flight cancellations due to the two storm fronts, and that number could grow on Wednesday.
At Atlanta's airport, the world's busiest, nearly 2,000 flights were canceled for a second straight day.
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In Chicago, a separate storm system was causing flight delays and 450 cancellations by early Tuesday afternoon at O'Hare.
The National Weather Service gave figures for the amount of snow which had fallen since Tuesday evening for a number of locations.
Stamford, Connecticut had 2.5 inches by 12 a.m.; Newark Airport had 3.7 inches by 1 a.m.; Brooklyn Heights in NYC had 2.5 inches by 12.15 a.m. while there were 4.5 inches in Central Park by 1.22 a.m.
In Maryland, Forte Meade got 2.1 inches by 10.56 p.m. Tuesday while Damascus had 2.5 inches by 10 p.m.
'Major winter storm'Connecticut's Department of Emergency Management & Homeland Security said in a statement that radar images showed heavy snow falling across most of south and central parts of the state at 12:45 a.m. Wednesday.
"A band of very heavy snow is entering South Central and Southeastern CT at this time. A low pressure system currently located off the coast of Southern New Jersey at 1:00 a.m. will move North Northeast up the East Coast overnight," it said in a statement.
"This low pressure system is continuing to rapidly intensify into a major winter storm as it spreads heavy snow over Southern New England at this time," it added.
Winter storm warnings were in effect for most of southern and eastern New England Wednesday.
The statement said snow was forecast to fall at a rate of 2 to 3 inches an hour, but warned this could increase to 4 to 5 inches an hour for a few hours in some towns in central and southeastern parts of the state.
It said that the department expected there would be 10 to 18 inches of snow on the ground by the Wednesday morning rush hour, adding that visibility was likely to be "very low." Temperatures were expected to stay in the mid 20s.
By the afternoon, the snowfall was expected to be moderate but there would still be considerable blowing and drifting snow during the afternoon rush hour, the statement said.
Total snowfall could range from 15 to 25 inches statewide, it added.
New York City confronted its third snowstorm in less than three weeks. On Tuesday, it declared a weather emergency and Mayor Michael Bloomberg's administration admitted mistakes in its handling of the Christmas weekend blizzard and promised immediate changes.
"We didn't do the job that New Yorkers rightly expect of us in the last storm and we intend to make sure that that does not happen again," Bloomberg told a news conference.
Bloomberg said the heaviest snowfall is expected just before rush hour in New York on Wednesday morning and asked commuters not to drive if possible.
National Weather Service forecasters predicted 6 to 12 inches of snow starting in New York late Tuesday night and continuing through Wednesday.
The previous storm — the sixth largest in city history — dumped 20 inches on New York's Central Park over 17 hours on December 26 and 27.
'A lot of snow'National Weather Service forecaster Michael Eckert said that while this storm will not be as strong and widespread, "for a major metropolitan area, this is still a lot of snow and will cause some disruption."
Boston, where a blizzard warning was issued, could see up to 16 inches of snow.
Boston Mayor Thomas Menino late Tuesday declared a snow emergency, which bans parking ban on all major streets and cancels public schools.
In the South, low temperatures Tuesday were expected to keep snow and ice on the ground a day after snow ranging from several inches to more than a foot blanketed states from Louisiana to the Carolinas — a region where many cities have only a handful of snow plows, if any.
Freezing rain in some areas added to the misery and schools around the region remained closed for a second day.
In Atlanta, trucker Vernon Cook, 67, said he's been stuck on an interstate ramp for almost 24 hours in a long line of tractor trailers that can't move because of the ice.
"I've been a trucker for 46 years and have seen nothing like this," said Cook.
"The road conditions are very dire at this point," Joe Turner, a North Carolina transportation maintenance engineer in Raleigh, said early Tuesday. "The roads are very bad. We urge people to stay at the house."
At least 11 people have been killed in weather-related traffic accidents. In a bid to avoid further accidents, authorities shut schools and government offices for a second day in dozens of districts in Georgia, Alabama, Mississippi, North and South Carolina and Tennessee.
Atlanta's normally bustling downtown area was nearly deserted for the second day in a row Tuesday.
More than 300 passengers who were stranded at an Atlanta bus station were given sandwiches, blankets and bottled water from a nearby jail. Several other charities and local restaurants have also brought food.
"It's a whole lot better than nothing," police spokesman Officer Curtis Davenport said.
Some bus travelers tried to get some sleep in chairs or on the floor.
Greg Walton, of Orlando, Fla., said his bus started losing traction and the battery eventually died when it neared Atlanta. He's been stuck at the station since being ferried there on a another bus Monday.
"They bring us here, then they just declared martial law on us," he said, jokingly.
In North and South Carolina, thousands were without power.
Most of North Carolina remained under a winter storm warning.
Conditions were unlikely to improve anytime soon. Temperatures should stay below freezing for days, and more snow is predicted. That means treacherous travel conditions could persist until Wednesday or beyond.
Slideshow 32 photos
Snow blankets the Northeast after hitting the South
"The problem here is that they're not used to it, so the equipment and the sanitation removal and the snow removal is not really geared for this kind of situation," said Tino Grana, of New York City, who traveled to Atlanta to sell art at a downtown trade show.
Atlanta, which got 4 to 7 inches, has just eight snow plows. The city hired a fleet of 11 privately run trucks to help spread salt and gravel.
The weather began rolling across the South on Sunday, coating bridges and roads with snow, sleet and freezing rain. The governors of Alabama, Georgia, Louisiana, North Carolina, South Carolina and Tennessee declared emergencies.
Drivers struggled to stay on slippery pavement, and roads were littered with abandoned vehicles. Some motorists got out in the middle of interstates to push their cars up ice-covered ramps.
"Towns down here just don't have the equipment to deal with this much snow," said Joel Weems, a worker at the University of Mississippi.