Tropical Storm Ernesto churned away from Bermuda on Sunday and headed further out in the northeastern Atlantic, but it still sent powerful swells toward the U.S. East Coast, generating rip currents associated with at least one death and prompting many rescues.

The National Weather Service posted a coastal flood advisory and warned of a high risk for rip currents along the Atlantic Coast through Monday evening, saying they “can sweep even the best swimmers away from shore into deeper water.”

A warning extended from Florida to the Boston area and portions of Maine.

In periods of high risk, rip currents become more likely and potentially more frequent, posing a danger to all levels of swimmers, not just inexperienced ones, said meteorologist Mike Lee in Mount Holly, New Jersey.

“It’s going to be really dangerous out in the water today,” he said.

At Manasquan Inlet in New Jersey, officials said a fisherman was washed off the north jetty Saturday but was quickly rescued by lifeguards. The victim had knee and back injuries and a possible concussion and was taken to a hospital, Lifeguard Chief Doug Anderson told NJ Advance Media, and lifeguards rescued at least five other people.

In Ventnor to the south, Senior Lt. Meghan Holland of the city beach patrol said eight people were rescued.

Forecasters, citing local emergency management, said a 41-year-old man drowned Saturday in a rip current at Surf City, North Carolina.

Two men drowned Friday in separate incidents on Hilton Head Island, South Carolina, but it was unclear whether rip currents were involved, The Island Packet of Hilton Head reported, citing a lifeguard services spokesperson.

The rough surf contributed to an unoccupied beach house along the Cape Hatteras National Seashore on North Carolina’s Outer Banks collapsing into the water Friday evening. Seashore officials urged the public Sunday to avoid beaches in parts of the village of Rodanthe where “substantial damage” to several oceanfront structures has occurred. Debris cleanup was expected over the next several days.

Flash flood warnings were posted for parts of Connecticut and southeastern New York, and flash flood watches and advisories were in effect for areas of Delaware, New Jersey and southeastern Pennsylvania, with forecasters warning of floods in low-lying areas.

On New York’s Long Island, East Hampton Village Mayor Jerry Larsen said beaches were closed to swimmers on Saturday and Sunday because high tides pushed water right up to the base of the dunes “so you can’t really have people sitting on the beach.”

Many people watched the water from the parking lot Sunday, he added.

“It’s quite a sight to see the water coming up almost to the parking lot, and if you think about it that storm was hundreds of miles offshore so it must have been quite powerful,” Larsen said.

The annual fireworks show that draws thousands was canceled Saturday night and again for Sunday night, he said.

Ernesto weakened to a tropical storm late Saturday after bringing heavy rain and strong winds to Bermuda but was expected to strengthen later to a hurricane again as it headed into the northeastern Atlantic.

Businesses were beginning to reopen in the tiny British territory after the storm passed and “we are on our way back to living a life of normalcy,” said Bermuda Security Minister Michael Weeks on Sunday.

There were no reports of major damage, said Lyndon Raynor of Bermuda’s Disaster Risk Reduction Mitigation Team. BELCO, Bermuda’s power company, said 50% of customers had electricity but more than 8,000 remained without it Sunday.

Ernesto previously battered the northeastern Caribbean, leaving tens of thousands of people without water in Puerto Rico. The national power company LUMA said it had restored electricity to more than 1.4 million customers, but service data Sunday showed more than 59,000 without power.

After cleaning up and removing debris, the Virgin Islands Department of Education said all public schools would resume operations Monday. Public school classes also were slated to start Monday in Puerto Rico, nearly a week after the original opening date.

Gary Robertson in Raleigh, North Carolina, Julie Walker in New York and Mariana Martínez Barba in Mexico City contributed.