HAMPTON, N.H. (AP) – A new flag system is operating at the state’s five Seacoast beaches to warn swimmers and surfers about dangerous riptides.

The warning system was developed after two swimmers drowned in riptides near Hampton Beach last July. The undertow can pull swimmers into deep water. Anyone caught in a riptide is advised to swim parallel to the shore until they’re free of the undertow and can swim in.

The color-coded flags include green ones to signal low risk for riptides and red to alert beachgoers to high risk conditions.

“It’s a good idea,” said Cheryl Houde, of Tewksbury, Mass., a mother of two. “Do I think it will stop everyone? No. We were here last year a day before one of the people drowned. A lot of people are thrill seekers and they’ll want to go in anyway.”

Amy Bassett, spokeswoman for the state Division of Parks & Recreation, said swimmers should be careful even when a green flag is shown. Ratings can change depending on the time of day and the section of beach.

“One part of the beach can be rated green and another can be red,” she said.

Hampton Beach is considered the main danger spot for riptides, especially about three hours before and after low tide.

There, signs have been placed at staircases leading to the beach and near bathrooms explaining what rip currents are and how to swim out of them.

Hampton Beach also added a new tow sled to its rescue equipment to make it easier for lifeguards to transport stranded swimmers back to shore.