By RON TODT, Associated Press

Tropical Storm Ernesto moved from Bermuda into the northeast Atlantic on Sunday, but still sent powerful waves toward the U.S. east coast, creating backwashes that resulted in at least one death and numerous rescue efforts.

The National Weather Service issued a flood warning and warned of a high risk of rip currents along the Atlantic coast through Monday evening, which could “sweep even the best swimmers from shore into deeper waters.”

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

During high-risk periods, rip currents become more likely and may occur more frequently, posing a danger to swimmers of all levels, not just inexperienced ones, said meteorologist Mike Lee of Mount Holly, New Jersey.

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

In New Jersey’s Manasquan Inlet, a fisherman was washed off the north pier on 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. Lifeguards rescued at least five other people.

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

Meteorologists reported, citing the local emergency management agency, that a 41-year-old man drowned in a rip current in Surf City, North Carolina, on Saturday.

Two men drowned in separate incidents on Hilton Head Island in the US state of South Carolina on Friday. It is unclear whether rip currents played a role, reported the “Island Packet” from Hilton Head, citing a lifeguard spokesman.

Rough surf contributed to an unoccupied beach house collapsing into the water at Cape Hatteras National Seashore on North Carolina’s Outer Banks Friday night. Coast Guard officials urged the public Sunday to avoid beaches in parts of the village of Rodanthe, where several oceanfront buildings sustained “significant damage.” Debris cleanup is expected in the next few days.

Flash flood warnings were issued for parts of Connecticut and southeastern New York, and flash flood warnings and advisories were in effect for areas of Delaware, New Jersey and southeastern Pennsylvania. Meteorologists warned of flooding in low-lying areas.

Jerry Larsen, mayor of East Hampton Village on Long Island, New York, said the beaches were closed to swimmers on Saturday and Sunday because the water reaches the base of the dunes at high tide, “so you can’t really have people sitting on the beach.”

Many people looked at the water from the parking lot on Sunday, he added.

“It’s an impressive sight when the water almost reaches the parking lot. And considering the storm was hundreds of miles offshore, it must have been pretty severe,” Larsen said.

The annual fireworks display, which attracts thousands of visitors, has been cancelled for Saturday night and again for Sunday night, he said.

Ernesto weakened to a tropical storm late Saturday after bringing heavy rains and strong winds to Bermuda, but it was later expected to restrengthen to a hurricane as it moved into the northeast Atlantic Ocean.

After the storm, businesses in the small British territory began to reopen and “we are on the way back to normal life,” Bermuda Security Minister Michael Weeks said 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 percent of customers had power, but more than 8,000 were without it on Sunday.

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

After cleanup and debris removal, the Virgin Islands Department of Education said all public schools would resume operations on Monday. Public schools in Puerto Rico were also scheduled to begin classes on Monday, nearly a week after the original opening date.