Dangerous surf and "life-threatening" rip currents could force more swimmers out of the ocean today as Hurricane Bill continues churning northward in the Atlantic.

Punishing waves and rip currents -- swift channels that can pull swimmers out to sea -- were produced by the storm Saturday, forcing lifeguards to close or restrict swimming at many East Coast beaches including Rehoboth in Delaware and Ocean City in Maryland. And though the hurricane had dropped to a Category 1 storm by Saturday evening, the National Hurricane Center in Miami warned that Bill could bring "extremely dangerous surf and ... rip currents to parts of the U.S. East Coast" before reaching Canada.

"It takes a while for the ocean to relax" after strong storms, said Gary Conte, a meteorologist with the National Weather Service. "Until it does, riptides will make dangerous sport" for surfers and swimmers.

Officials declared a tropical storm warning for the Massachusetts coast, including President Barack Obama's planned vacation spot of Martha's Vineyard, though the storm's eye was expected to stay offshore and pass that island before the president arrives today.

Red flags were posted Saturday on beaches along the Eastern Seaboard, keeping swimmers out of the water on the hot, humid day.

Rehoboth Beach Patrol Capt. Kent Buckson said many swimmers there were not happy because the ocean had a deceptively calm appearance most of the time. Every few minutes, though, waves would spike to 10-foot heights. Those not familiar with the force of breaking waves can be seriously injured, he said -- as a man was Friday when the heavy surf pounded him face-first into the Rehoboth sand. The man was airlifted to Christiana Hospital with serious injuries.

"Where the danger lies is when people are standing by the water line," Buckson said. "They think the waves are not as powerful, then they get pile-driven into the beach."

Today, Buckson said, wave heights could reach 12 to 15 feet. Getting hit by such breakers is like having someone drop a 100-pound sack of water on you from a 10th-story hotel room, he said.

source: delawareonline.com