The beach is a popular place in the summertime. But there are dangers beneath the ocean surface. Here is a look at rip tides, also known as rip currents -- the science, the danger, and how to survive them.

Summer is a popular time for beach goers. But there are hidden dangers in the ocean. Rip tides, also called rip currents, are powerful, channeled streams of water flowing away from shore, through the surf zone, and past the line of breaking waves.  They can occur on any beach with breaking waves, and they can kill.

The U.S. Lifesaving Association says rip tides claim more than 100 lives in the United States alone each year. It says more than 80 percent of life-saving rescues are due to rip tides.

The phenomenon works like this -- a sand bar traps the water from incoming waves, creating something like a pond.  When that sand bar breaks, the water in that pond rushes out to sea.  That is the sometimes-powerful rip tide.

Lifeguard Bill Soltz

Lifeguard Bill Soltz explains, "All of a sudden, the current just starts pulling them into slightly deeper water and that is when they start panicking."

Experts recommend you swim only in areas monitored by lifeguards.   Florida officials say rip tide related rescues have increased there, probably due to sandbar changes brought on by last year's hurricanes.

Lifeguards are trained to swim away from rip tides before trying to reach shore. That is not what most swimmers naturally do, says Barbara Payne. "That's the classic error.  You keep swimming. You tire yourself out."

Barbara Payne

She, her daughter and two cousins, almost died in a rip tide. Recounting her experience, "I just kept thinking if we swim hard enough, we'll get there but of course, that's not how it works."

Lifeguards say don't panic, don't fight, go with the current, even as it pulls you out. Then swim to the side to get out of it. You should be free from the swift current in 20-to-30 seconds. Then you'll be able to swim to shore in calmer water.