Swimmers flocked to South Shore beaches Thursday as scorching temperatures blanketed Long Island, but lifeguards at Robert Moses State Park are warning beachgoers about the dangers of rip currents.

The warning comes just two days after five people were caught in a rip current after lifeguards had gone off duty at Robert Moses. Three off-duty lifeguards rescued all five swimmers.

Josh Friedman, captain at Robert Moses Field 3, said rip currents can pull even experienced swimmers away from shore within seconds.

“The sweep takes them down and all of a sudden they fall off the shelf into the rip and now they’re 50 yards out, and they can’t swim,” Friedman said. “They were just standing and now they’re 50 yards off shore.”

Friedman said there were no rip current rescues Thursday, but conditions can change quickly, especially later in the day.

Lifeguards urge swimmers to stay out of the water when lifeguards are not on duty. If caught in a rip current, officials say not to panic. Instead, swim parallel to the shoreline until you are out of the current, then head back to shore. Swimmers are also encouraged to always enter the water where lifeguards are on duty.