Barely a hurricane on Sunday but massive and packed with rain, Irene flooded towns, killed at least eight people and knocked out power to more than 2 million homes and businesses as it plodded up the East Coast, saving the strongest winds it had left for New York.
The streets of the nation's largest city were eerily quiet, its transit system shut down because of weather for the first time in history.
Mayor Michael Bloomberg warned late Saturday that no matter whether residents of low-lying areas heeded his calls to evacuate, "The time for evacuation is over. Everyone should now go inside and stay inside."
The National Hurricane Center said that although tropical-storm-force winds covered a vast area of the mid-Atlantic states early Sunday morning, the only hurricane-force winds — 74 mph or above — covered a relatively small area over the Atlantic Ocean, east of the storm's center.
Those winds were expected to retain hurricane strength until they finally reached land around midday Sunday over New York's Long Island.
Tornadoes were reported in Maryland and Delaware, and several warnings were issued elsewhere, including New York and Philadelphia.
Irene caused flooding from North Carolina to Delaware, both from the seven-foot waves it pushed into the coast and from heavy rain.
Eastern North Carolina got 10 to 14 inches of rain, according to the National Weather Service. Virginia's Hampton Roads area was drenched with at least nine inches, with 16 reported in some spots.
More than 1 million homes and businesses lost power in Virginia alone, where three people were killed by falling trees, at least one tornado touched down and about 100 roads were closed.
Emergency crews around the region prepared to head out at daybreak to assess the damage, though with some roads impassable and rivers still rising, it could take days.
Some held out optimism that their communities had suffered less damage than they had feared.
"I think it's a little strong to say we dodged a bullet. However, it certainly could have turned out worse for the Hampton Roads area," said National Weather Service meteorologist Mike Montefusco.
In North Carolina, where at least two people were killed, Gov. Beverly Perdue said Irene inflicted significant damage along the North Carolina coast and some areas were unreachable.
"Folks are cut off in parts of North Carolina, and obviously we're not going to get anybody to do an assessment until it's safe," she said.
Television coverage showed evidence of damage across eastern North Carolina with downed trees and toppled power lines.
A falling tree also killed one person in Maryland. A surfer and another beachgoer in Florida were killed in heavy waves caused by the storm.
The storm arrived in Washington just days after an earthquake damaged some of the capital's most famous structures, including the Washington Monument. Irene could test Washington's ability to protect its national treasures and its poor.
A nuclear reactor at Maryland's Calvert Cliffs went offline automatically when winds knocked off a large piece of aluminum siding that came into contact with the facility's main transformer late Saturday night.
An 'unusual event'was declared, the lowest of four emergency classifications by the Nuclear Regulatory Commission, but Constellation Energy Nuclear Group spokesman Mark Sullivan said the facility and all employees were safe.
Near Callway, Md., about 30 families were warned that a dam could spill over, causing significant flooding, and that they should either leave their homes or stay upstairs. St. Mary's County spokeswoman Sue Sabo said the dam was not in danger of breaching.
Irene made its official landfall just after first light near Cape Lookout, N.C., at the southern end of the Outer Banks, the ribbon of land that bows out into the Atlantic Ocean. Shorefront hotels and houses were lashed with waves, two piers were destroyed and at least one hospital was forced to run on generator power.
Across the Eastern Seaboard, at least 2.3 million people were under orders to move to somewhere safer, though it was unclear how many obeyed.
Annette Burton, 72, was asked to leave her Chester, Pa., neighborhood because of danger of rising water from a nearby creek.
She said she planned to remain in the row house along with her daughter and adult grandson, although with a wary eye on the park across the street that routinely floods during heavy rains.
"I'm not a fool; if it starts coming up from the park, I'm leaving," she said. "It's the wind I'm more concerned about than anything."
As the storm's outer bands reached New York on Saturday night, two kayakers capsized and had to be rescued off Staten Island.
They received summonses and a dressing-down from Bloomberg, who said at a press conference that they recklessly put rescuers' lives at risk.
The storm hugged the U.S. coastline on a path that could scrape every state along the coast. By Sunday morning, it had sustained winds of 75 mph, down from 100 mph on Friday.
That made it a Category 1, the least threatening on a 1-to-5 scale, and barely stronger than a tropical storm.
Nevertheless, it was still considered highly dangerous, capable of causing ruinous flooding with a combination of storm surge, high tides and 6 to 12 inches of rain.
"Everything is still in effect," National Hurricane Center spokesman Dennis Feltgen said. "The last thing people should do is go outside. They need to get inside and stay in a safe place until this thing is over."
Pennsylvania Gov. Tom Corbett warned that the state will not necessarily be out of danger once the storm has passed: "The rivers may not crest until Tuesday or Wednesday. This isn't just a 24-hour event."
Ed Rappaport, deputy director of the National Hurricane Center in Florida, said the storm is so large that areas far from Irene's center are going to be feeling strong winds and getting large amounts of rain, he said.
"It is a big, windy, rainy event," he said. Irene was the first hurricane to make landfall in the continental United States since 2008, and came almost six years to the day after Katrina ravaged New Orleans on Aug. 29, 2005. Experts said that probably no other hurricane in American history had threatened as many people.
Defense Secretary Leon Panetta told 6,500 troops from all branches of the military to get ready to pitch in on relief work, and President Barack Obama visited the Federal Emergency Management Agency's command center in Washington and offered moral support.
"It's going to be a long 72 hours," he said, "and obviously a lot of families are going to be affected."
In New York, authorities undertook the herculean job of bringing the city to a halt. The Metropolitan Transportation Authority shut down its subways, trains and buses for a natural disaster for the first time, a job that began at noon Saturday and took into late that night to complete.
On Wall Street, sandbags were placed around subway grates near the East River because of fear of flooding.
Tarps were spread over other grates. Construction stopped throughout the city, and workers at the site of the World Trade Center dismantled a crane and secured equipment.
The city was far quieter than on an average Saturday. In some of the busiest parts of Manhattan, it was possible to cross a major avenue without looking, and the waters of New York Harbor, which might normally be churning from boat traffic, were quiet.
About 370,000 people living in low-lying areas of the city, mostly in Lower Manhattan, Brooklyn and Queens, were under orders to clear out.
New York has seen only a few hurricanes in the past 200 years. The Northeast is much more used to snowstorms — including a blizzard last December, when Bloomberg was criticized for a slow response.
Airlines said 9,000 flights were canceled, including 3,000 on Saturday. The number of passengers affected could easily be millions because so many flights make connections on the East Coast.
Greyhound suspended bus service between Richmond, Va., and Boston. Amtrak canceled trains in the Northeast for Sunday.
In Philadelphia, Mayor Michael Nutter declared a state of emergency, the first for the city since 1986, when racial tensions were running high. "We are trying to save lives and don't have time for silliness," he said.
In New Jersey, the Oyster Creek nuclear plant, just a few miles from the coast, shut down as a precaution as Irene closed in.
And Boston's transit authority said all bus, subway and commuter rail service would be suspended all day Sunday.