Whipping up trouble before ever reaching land, Hurricane Irene zeroed in Friday for a catastrophic run up the Eastern Seaboard. More than 2 million people were told to move to safer places, and New York City ordered its entire subway system shut down for the first time because of a natural disaster.
As the storm's outermost bands of wind and rain began to lash the Outer Banks of North Carolina, authorities in points farther north begged people to get out of harm's way. The hurricane lost some strength but still packed 100 mph winds, and officials in the Northeast, not used to tropical weather, feared it could wreak devastation.
"Don't wait. Don't delay," said President Obama, who decided to cut short his summer vacation on Martha's Vineyard off Massachusetts by a day and return to Washington. "I cannot stress this highly enough: If you are in the projected path of this hurricane, you have to take precautions now."
The National Hurricane Center said the storm is unlikely to get any stronger and may weaken slightly before reaching land. It said Irene could weaken into a tropical storm before reaching New England, but that even below hurricane strength it would be a powerful and potentially destructive storm.
Hurricane warnings were issued from North Carolina to New York, and watches were posted farther north, on the islands of Nantucket and Martha's Vineyard.
Evacuation orders covered at least 2.3 million people, including 1 million in New Jersey, 315,000 in Maryland, 300,000 in North Carolina, 200,000 in Virginia and 100,000 in Delaware.
"This is probably the largest number of people that have been threatened by a single hurricane in the United States," said Jay Baker, a geography professor at Florida State University.
New York City ordered more than 300,000 people who live in flood-prone areas to leave, including Battery Park City at the southern tip of Manhattan, Coney Island and the beachfront Rockaways. But it was not clear how many would do it, how they would get out or where they would go. Most New Yorkers don't have a car.
On top of that, the city said it would shut down the subways and buses at noon today, only a few hours after the first rain is expected to fall. The transit system carries about 5 million people on an average weekday, fewer on weekends.
Mayor Michael Bloomberg said there was little authorities could do to force people to leave. "We do not have the manpower to go door-to-door and drag people out of their homes," he said. "Nobody's going to get fined. Nobody's going to go to jail. But if you don't follow this, people may die."
Shelters were opening Friday afternoon, and the city was placed under its first hurricane warning since 1985.
Transit systems in New Jersey and Philadelphia also announced plans to shut down, and Washington declared a state of emergency.
New Jersey Gov. Chris Christie demanded people "get the hell off the beach" in Asbury Park and said: "You're done. Do not waste any more time working on your tan."
Hundreds of thousands of airline passengers were grounded for the weekend. JetBlue Airways said it was scrubbing about 880 flights between today and Monday, most to and from hub airports in New York and Boston.
The five New York-area airports will be closed beginning at noon today to arriving passenger flights. The Port Authority of New York and New Jersey, which operates the airports, said many weekend departures also have been canceled.
The Port Authority said it was taking the action to avoid stranding passengers at the airports since the region's transit system will be closed.
Thousands of people were already without power. In Charleston, S.C., several people had to be rescued after a tree fell on their car.
Defying the orders, holdouts in North Carolina put plywood on windows, gathered last-minute supplies and tied down boats. More than half the people who live on two remote islands, Hatteras and Ocracoke, had ignored orders to leave. The last ferry from Ocracoke left at 4 p.m. Friday.
Officially, Irene was expected to make landfall today near Morehead City, on the southern end of the Outer Banks, the barrier island chain. But long before the eye crossed the coastline, the blustery winds and intermittent rains were already raking the coast. By Friday evening 50 mph winds were measured at Wrightsville Beach, N.C.
National Hurricane Center meteorologist David Zelinsky said earlier Friday that he expected the storm to arrive as a Category 2 or 3 hurricane. Later in the day, other forecasts showed it would strike most of the coast as a Category 1.
Regardless of how fierce the storm is when it makes landfall, the coast of North Carolina was expected to get winds of more than 100 mph and waves perhaps as high as 11 feet, Zelinsky said.
"This is a really large hurricane, and it is dangerous," he said. "Whether it is a Category 2 or 3 at landfall, the effects are still going to be strong. I would encourage people to take it seriously."
After the Outer Banks, the next target for Irene was the Hampton Roads region of southeast Virginia, a jagged network of inlets and rivers that floods easily. Emergency officials have said the region is more threatened by storm surge, the high waves that accompany a storm, than wind. Gas stations there were low on fuel Friday, and grocery stores scrambled to keep water and bread on the shelves.
In Delaware, Gov. Jack Markell ordered an evacuation of coastal areas.
Officials at Walter Reed Army Medical Center in Washington said they were speeding the transfer of their last remaining patients to the National Naval Medical Center in Bethesda, Md. The transfer had been planned for Sunday.
In Baltimore's Fells Point neighborhood, one of the city's oldest waterfront neighborhoods, people filled sandbags and placed them at the entrances to buildings. A few miles away at the Port of Baltimore, vehicles and cranes continued to unload huge cargo ships that were rushing to offload and get away from the storm.
In New York, the Mets postponed games scheduled for today and Sunday with the visiting Atlanta Braves, and the Jets and Giants moved their preseason NFL game up to 2 p.m. today from 7 p.m. but then postponed it until Monday.
In Atlantic City, N.J., all 11 casinos announced plans to shut down Friday, the third time that has happened in the 33-year history of legalized gambling in that state.