Thousands more were ordered to leave their homes in New Jersey, New York and Maryland. Rescue helicopters plucked residents from rooftops as rivers and streams surged over their banks, washed out roads and bridges, and cut off villages in some of the worst flooding in the region in decades.
Wilkes-Barre, a northeastern Pennsylvania city that was devastated by deadly flooding in 1972 from the remnants of Hurricane Agnes, is protected by levees, and officials said the Susquehanna was expected to crest just a few feet from the tops of the 41-foot floodwalls.
But Luzerne County Commissioner Todd Vonderheid said officials were worried about the effects of water pressing against the levees for 48 hours. The floodwalls were completed just three years ago.
"It is honestly precautionary," Vonderheid said. "We have great faith the levees are going to hold."
An estimated 150,000 to 200,000 people in the county of about 351,000 were told to get out by nightfall. The evacuation order applied to much of Wilkes-Barre and several outlying towns, all of them flooded by Agnes more than three decades ago.
CBS News national correspondent Byron Pitts reports that in neighborhood after neighborhood, the scene was the same — families packing what they could, as fast as they could.
Laura Lockman, 42, of Wilkes-Barre packed a car and planned to clear out along with her husband, three kids and a puppy named Pebbles. They were not ordered to evacuate their brick home, a half-mile from the Susquehanna, but were going to nearby Scranton anyway for the children's safety. Their home was inundated in 1972, when water reached the second floor.
"I just want to get out of here. I just want to be safe, that's all," she said.
A dozen helicopters from the Pennsylvania National Guard, the state police and the Coast Guard were sent on search-and-rescue missions, plucking stranded residents from rooftops in Bloomsburg, Sayre and New Milford. Hundreds of National Guardsmen prepared to distribute ice, water and meals ready to eat.
Flooding closed many roads in the Philadelphia area, including the Pennsylvania Turnpike.
"We lost just about everything — the cars, the clothes, even the baby's crib," said James Adams, who evacuated his family's home near Binghamton, N.Y., after watching their shed float away and their cars get submerged. "I'm not sure what we are going to do."
Elsewhere in the Binghamton area, an entire house floated down the Susquehanna.
The soaking weather was produced by a low-pressure system that has been stalled just offshore since the weekend and pumped moist tropical air northward along the East Coast. A record 4.05 inches of rain fell Tuesday at Binghamton. During the weekend, the same system drenched the Washington and Baltimore region with more than a foot of rain.
CBS News correspondent Susan Roberts reports flooding in the nation's capital has closed has closed headquarters of the Internal Revenue Service, the Museum of Natural History and the National Archives.
All Smithsonian museums are closed as well, CBS News correspondent Joie Chen adds.
None of the flooded buildings had structural damage, but water in the basements damaged air-conditioning, electric wires and others building systems, said Mike McGill, a spokesman for the General Services Administration, which manages federal buildings.
"We're still in the process of evaluating the damage to those systems," he said.
Sandbags were set up to prevent more water from getting inside.
Officials at the Justice Department, which handles day-to-day operations it its headquarters, said it could take a week to clean up the mess there and reopen the building.
The National Archives moved in giant dehumidifiers to preserve its historic documents. "The threat to the records is not floodwater, but humidity from the lack of air conditioning," spokeswoman Susan Cooper said Wednesday.
Easier to clean up, but perhaps more dramatic: word that the elm tree which fell over at the White House due to the storms is part of our history - and was the model for the drawing on the back of the $20 bill.
Pitts reports concerns center around three river basins — the Susquehanna, the Delaware and the Mohawk. In Wilkes-Barre, that water in the Susquehanna is flowing at a rate of 1.7 million gallons per second.
An estimated 2,200 people were ordered to evacuate the area around Lake Needwood at Rockville, Md., which was approaching 25 feet above normal. Engineers reported weakened spots on the lake's earthen dam.
A swollen creek carved a 25-foot-deep chasm through all four lanes of Interstate 88, about 35 miles northeast of Binghamton, N.Y., and two truckers were killed early Wednesday when their rigs plunged into the gaps, officials said.
Thousands of people were evacuated from communities across New York state, and whole villages north of Binghamton County were isolated by high water.
Along the Delaware River, more than 1,000 people left low-lying areas of Trenton, N.J., and state employees in buildings along the river left work early.
Trenton's water filtration system was shut down because of debris floating down the Delaware, and Mayor Doug Palmer called for conservation, saying the city had only about two days of drinkable water. The river was expected to crest Friday at nearly 8 feet over flood stage, the fourth-highest level on record for Trenton.
The weather was blamed for four deaths each in Maryland and Pennsylvania, one in Virginia and three in New York, including the two truckers.
The Agnes flood caused 50 deaths and more than $2 billion in damage in Pennsylvania, and remains the worst natural disaster in state history. It left 20,000 families homeless in Wilkes-Barre and surrounding Luzerne County towns.
Afterward, the U.S. Army Corps of Engineers undertook one of the most ambitious flood-control projects east of the Mississippi River, raising the existing levees by 3 to 5 feet. The $200 million project was finally completed in 2003.