Forecasters expect the storm to peak over the next 48 hours and say it could re-intensify into a major hurricane by Wednesday night.
While Erin is unlikely to make landfall along the East Coast before turning farther out to sea, authorities expect its large swells will cut off roads to villages and vacation homes on North Carolina's Outer Banks and whip up life-threatening rip currents from Florida to New England.
New York City closed its beaches to swimming on Wednesday and Thursday. Some beaches in New Jersey, Maryland and Delaware also will be temporarily off-limits.
Off Massachusetts, Nantucket Island could see waves of more than 10 feet later this week. But the biggest threat remained along the Outer Banks.
Despite the beach closures, some swimmers were continuing to ignore the warnings. Rescuers saved more than a dozen people caught in rip currents Tuesday at Wrightsville Beach in North Carolina -- a day after more than 80 people were rescued.
Bob Oravec, the lead National Weather Service forecaster in College Park, Maryland, said even if someone thinks they know how to handle a rip current, it’s still not safe in the current conditions.
“You can be aware all you want,” he said. “It can still be dangerous.”
A combination of fierce winds and huge waves — estimated to be about 20 feet in height — could cause coastal flooding in many beachfront communities, North Carolina officials warned on Wednesday.
“Regardless of the track of the center of the storm, dangerous conditions can be felt far from the eye, especially with a system as large as Erin,” said Will Ray, the state’s emergency management director.
Dozens of beach homes already worn down from chronic beach erosion and the loss of protective dunes could be at risk, said David Hallac, superintendent of the Cape Hatteras National Seashore.
Water from the Atlantic already was washing onto the main route through the Outer Banks on Wednesday, and some sections are likely to be impassable during high tide later in the evening.
Authorities warned that time was running out to leave, but most residents decided to stay despite evacuations ordered on Hatteras and Ocracoke Islands.
“We probably wouldn't stay if it was coming directly at us,” said Rob Temple, who operates sailboat cruises on Ocracoke.
Erin has become an unusually large and deceptively worrisome storm, with its tropical storm winds covering 500 miles from edge to edge — roughly the distances from New York City to Pittsburgh.
