Deadly Danger: Rip Currents

Every year, rip currents pull about 100 swimmers to their deaths, for the most part without a lifeguard in sight.

CBS News Correspondent Sharyn Alfonsi explains that the rip currents are formed when water, wind and beach conditions combine to create rapidly moving channels of water that flow away from the shoreline, typically through narrow passages in a sandbar.

Alfonsi spoke with some scientists who are seeing what they can do to help, such as those at the University of Delaware's Center for Applied Coastal Research, where a wave tank recreates rip currents.

"Immediately, the dye begins to collect, condense, and begins to head offshore through the breaking wave pattern," says Assistant Professor Jack Puleo.

Researchers use the dyes and plastic floats to track the current, which typically lets up just beyond the breakers.

Which leads to some basic advice from Puleo: "Don't panic. Let the rip current carry you out. Don't fight it. Once you get out past the breaker zone, then paddle along the beach, and you'll come back in, and you'll actually have the waves helping you, essentially trying to push you back to shore. ...You can't beat the current. It just can't be done."

The wave tank scenarios are used in conjunction with computer models to better understand what's happening on the beach, where researchers also hope video images could soon help both lifeguards and swimmers.

"They could watching, essentially, the entire stretch of coastline in their town, and trying to decide if there are hotspots and places they have to look out for," observes the University of Deleware's Prof. James Kirby.

Posted signs now warn beachgoers how to avoid rip currents.