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Friday, November 16, 2001

Heres how you can avoid
losing your life in a riptide

While driving to school last week, my sister Michele phoned with some sad news she heard on the radio: "A tourist drowned at Sunset. She got caught in a riptide."

News of a drowning is always terrible, but drowning in a rip is particularly so because it's often avoidable.

"That's awful," I said. "If only she had known what to do."

"That's why I'm calling," Michele said. "I don't know what to do. I don't even know what a riptide is."

I was shocked. Had I really let my Midwest-raised sister live on the North Shore without teaching her the ins and outs of Hawaii's waves? Apparently so.

Well, she knows now. Here's what I told her:

When a wave breaks on a beach, the water that runs up the beach soon reverses course and flows back down the beach to the ocean. This is called the backwash.

Backwash from big waves can be dangerous anytime, but it is particularly so on steep beaches. Receding water picks up speed as it flows downhill, so the backwash of a large wave on a steep beach can be strong enough to knock you down and drag you out.

And backwash causes other problems. Because waves break one behind the other, incoming waves often push previous backwash sideways. This results in water running along the shoreline like a stream until it finds an exit, which is a low point in the reef or sand. There it flows back to sea.

This outward flow is a riptide or, more accurately, a rip current.

Rips often look flat and rippling, like rivers, and behave like rivers, too. Their fastest flow of water is in the middle. As you move toward the sides, the current slows.

Also like rivers, rips peter out when they spread wide. Rip currents, therefore, disappear when they reach the open water outside the waves.

"What about the undertow?" my sister wanted to know. "Doesn't it pull you under and hold you down?"

An undertow occurs where waves are breaking over rips. The force of the wave pushes the outgoing water down, creating an undertow. This downward force, however, lasts only a few seconds, because as soon as the wave breaks, the rip surfaces and so do you.

It's scary (OK, terrifying), but if you keep your wits about you, you can survive an undertow.

For most of us, getting caught anywhere in big surf would be a nightmare, but it's one we can live to talk about if we remember the following (and yes, Michele, there will be a quiz):

1. First and foremost, if you aren't experienced, stay away from big surf. Even if you see others in the waves, don't be tempted. Those people know what they're doing.

2. If you get swept into the ocean, don't try swimming against the current.

Tread water, breathe deep and get your bearings. If you do nothing else, the rip current will carry you outside the breaking waves where rescue workers can reach you.

3. Another option in a rip, if you can make out what's happening, is to swim sideways until the current eases. Then head to shore along the edge, where the rip stops and the waves start.

4. If a wave looks like it's going to break on you, take a deep breath and dive under it. Don't try to go over it.

5. If an undertow pulls you down, take a deep breath and wait it out. You'll come up naturally in a few seconds.

6. Above all, don't give in to panic. This is easy to say and hard to do, but that alone, staying calm, is probably what's going to save your life.

 

 

Marine biologist Susan Scott writes the newspaper column, "Ocean Watch",
for the Honolulu Star-Bulletin, www.starbulletin.com