Less than 24 hours after a Brooklyn man drowned at Ocean Beach Park in Long Beach, the city early Tuesday closed beaches to swimmers.

Heavy surf and treacherous rip currents were expected to continue throughout the day, with Hurricane Gaston churning the Atlantic Ocean one thousand miles to the southeast.

“The water is very big and the rips are bad,” said Long Beach Lifeguard Chief Paul Gillespie. “We’re not letting anyone in except the surfers.”

He warned swimmers: “The number one rule is, do not go in the water when lifeguards are not on duty.”

The dead man, who Long Beach police identified as Lorenzo Alvarez-Rodolfo, 26, was one of two men lifeguards pulled from the water at Edwards Boulevard at 6:24 p.m. Monday.

Lifeguards had gone off duty at 6 p.m. but responded to a call from police, he said. A third man who was with them swam to shore on his own, Gillespie said.

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Hurricane Gaston may be well to the east of Long Island’s South Shore, but its 105 mile-per-hour winds are having a powerful affect on local waters, National Weather Service meteorologist Gary Conte said, with waves up to seven feet on the East End.

“The strong winds that are circulating around this system are moving toward the northwest, toward our coastlines on New Jersey and New York, producing these rip currents,” he said.

Officials restricted swimming at a number of Long Island beaches Tuesday. Bodyboarding was prohibited at state beaches and lifeguards were asking swimmers to stay close to the shore and lifeguard stands.

Islip was flying red flags and limiting the swimming area. Oyster Bay closed beaches to swimming for part of the morning, and Hempstead Town was restricting swimmers to knee-deep water at its beaches because of the conditions.

“We may be forced to make further restrictions,” town spokesman Mike Deery said. “We’ll do that as our lifeguards and supervisors monitor the conditions.”