The massive winter whiteout across the eastern U.S. is disrupting air travel for approximaely one million people, said a government official. He said it will force the cancellation of the most flights since the terrorist attacks of September 11, 2001.
"This weather event likely will result in the in the most cancellations in a decade, with the exception of 9/11," David Castelveter, an official with the Air Transportation Association, told ABC News' Lisa Stark. "We calculate that approximately 13,000 ATA member carrier flights were canceled as a result of these weather events."
Though most carriers are expected to be operating near normal tomorrow, the cancellations will affect an estimated one million travelers, Castelveter said. Delta Airlines, which has its largest hub in Atlanta, has already canceled 700 flights there in anticipation of the three inches of snow are expected there Friday.
East Coasters waved the white flag today as they dug out -- again -- from under as much as two feet of snow. Wednesday's storm, the second to hit the Mid-Atlantic states in a week, has been blamed for widespread power outages, roof collapses and millions of dollars in cleanup costs.
Collapsed roofs were a major problem in the Mid-Atlantic region. A cell-phone video from Delaware showed the roof of a fire station caving in on the department's engine bay.
In Washington, D.C., fire crews searched an abandoned building after its roof buckled under the weight of two blizzards in a week.
"We have a large homeless population in our city," Dennis Rubin, chief of fire and emergency medical services, told "Good Morning America." "And you never know when a person tries to find refuge."
Even the Smithsonian suffered damage when a roof on its storage building collapsed.
Airports are reopening this morning up and down the East Coast, but it could take days to get back on schedule as the airlines try to move 400,000 people stranded and delayed by the storm.
Wednesday's storm broke a centuries-old seasonal snowfall record in the nation's capital -- more than 55 inches have fallen so far.
"I've never seen anything like this before. It's just a ghost town," said Lawrence Schultz, the D.C. Fire Department assistant chief of operations. "There is just nobody on the roads."
It took six firefighters to form a human crane to lift a car so they could rescue their fire truck from a snow bank. The city has been borrowing chains for their trucks from as far away as Philadelphia. The fire department has also used Google Earth imagery to find and dig out fire hydrants buried in the snow.
The federal government in Washington remained closed today for an unprecedented fourth day, costing an estimated $100 million a day in lost productivity.
Baltimore's snow tally this season has hit more than 79 inches, the most snow ever seen in the city since record-keeping began in 1893. A new snow total record was also set in Philadelphia.
In New York City, the 10 inches of snow that fell Wednesday wasn't enough to make the record books, but it slowed the city down.
Schools were closed for more than 1 million schoolchildren and road-weary plow drivers spent hours trying to keep up with the snowfall.
In total, 17 states were affected by the massive storm.
An estimated 110,000 people were left without electricity in Pennsylvania, and zero visibility was blamed for a 50-car pileup there that killed one person.
Forecasters say more snow is on the way with one storm heading into the southern states and a possible new storm hitting the Northeast by early next week.