Water hazard: how a teen saved a young boy from a potentially deadly beach danger.

DID YOU KNOW?

* Rip currents are often incorrectly referred to as riptides or undertow. Rip currents are not caused by Earth's tides. And undertow refers to the powerful flow of water that moves out to sea beneath incoming waves.

* Rip currents can form on any beach on which there is strong wave action. The currents sometimes form along beaches on large lakes, such as any of the Great Lakes.

CRITICAL THINKING:

* Lifeguards rarely close a beach because of rip currents. On ninny beaches, rip currents are so common that if the beaches were closed every time the currents occurred, people would rarely be allowed to swim. Do you think lifeguards should close a beach when they spot a rip current? Why or why not?

CROSS-CURRICULAR CDNNECTIONS:

ART: Design a sign that alerts beachgoers about the dangers of rip currents. The sign should capture beachgoers' attention, and inform them about how to escape a rip current should they be caught in one.

RESOURCES

* This Web site from the U.S. Lifesaving Association contains information about how to survive rip currents: www.usla.org/ripcurrents

* For more facts about rip currents, see: www.weather.com/activities/recreation/ boatandbeach/ripcurrents_overview.html

Sixteen-year-old Mackenzie Lothian has spent many afternoons bodysurfing the waves along Newport Beach in Southern California. For two summers, the avid swimmer even trained as a junior lifeguard--learning the ins and outs of ocean hazards. In April 2004, Mack's strong swimming skills and ocean know-how helped save the life of a young boy.

Mack rescued a boy who had become caught in a rip current. This powerful surge of water flows rapidly away from shore. Every year, more than 100 people die by drowning in these water surges. "Over 80 percent of lifeguard rescues are due to distress caused by rip currents," says B. Chris Brewster, president of the United States Lifesaving Association.

Hoping to save lives, scientists and beach-safety officials are trying to educate swimmers about the potentially deadly currents. As in Mack's case, knowledge about how rip currents work could be a lifesaver.

DANGER SIGN

Mack and his family were spending a day at the beach when he noticed a boy--who appeared to be about 9 years old--enter the ocean in an odd-looking spot: Waves were breaking, or tumbling over, on either side of the boy. But the water directly around him looked relatively calm. Mack was concerned. "I knew there was a rip current," he says.

What tipped him off? Waves break when the water shallows to a certain depth. On Newport Beach, the waves tumble when the water flows over a sandbar, or ridge of sand along the ocean bottom, that runs parallel to the beach. But where the boy went in, the waves weren't breaking. Mack knew that meant the ocean bottom was deeper there--there was a gap in the sandbar. Mack also knew that rip currents often form in these channels.

WATER TROUGH 

In most areas, water naturally flows toward and away from the beach as part of wave motion. The incoming waves crash onto the shore. Then, the water that's pushed onshore flows back out beneath new incoming waves. Sandbars like the one at Newport Beach can disrupt this back and forth wave motion. The ridge of sand slows the water's normal return to sea. Instead of quickly flowing back out, much of the water remains in the slight trough between the sandbar and the shore.

Rip currents frequently form when these water-blocking sandbars have gaps in them. Like a bathtub drain that's been unplugged, that opening becomes a more efficient route through which water in the trough can rush out to sea. The result: a rip current. These dangerous currents sometimes form under other conditions. "But most of the rip currents that people fall victim to are associated with gaps in sandbars," says James MacMahan, an ocean scientist at the University of Delaware.

GO WITH THE FLOW

As Mack had feared, the boy on Newport Beach had waded right into a rip current. Mack watched as the powerful flow of water knocked the boy off his feet and pulled him away from shore.

Mack knew that there wasn't a lifeguard on duty. "They were just periodically patrolling in a lifeguard truck," he says. So before the boy got too far out, Mack jumped into the rip current after him. Mack tried to calm the boy as the current pulled both of them away from shore--far from the view of Mack's family and the other beach-goers. Rip currents can move at speeds of up to 2.5 meters (8 feet) per second--faster than an Olympic swimmer. Still, Mack stayed calm. He knew that most rip-current victims become endangered because they get worn out while trying to swim back to shore against the speedy currents. "It's useless to fight it and swim headlong into shore," he says.

Instead, Mack held the boy and tried to swim parallel to shore. Because rip currents occur within a sandbar channel, the currents are usually less than 30.5 in (100 ft) across. Mack knew that they might be able to escape the current by swimming edgewise to the beach. Then, ocean waves moving toward shore would help return them to the beach (see Nuts and Bolts, above). But the weight of the boy was tiring Mack, and they weren't making very much progress.

STAY CALM

At that point, Mack knew that their best option was to just tread water; they could save their strength and try to get the attention of someone onshore. "At first we were moving out fast," explains Mack. "But then the rip current died down, and we stayed about 91 m (300 ft) from the beach." That's because rip currents are driven by huge amounts of water rushing through a narrow gap in the sandbar. Once the water moves past the outer edge of the sandbar and is able to spread out, the current's strength dies off.

Luckily, patrolling lifeguards soon passed by and spotted them in the waves. As a lifeguard helped the young boy, Mack swain out of the rip current and back to the beach.

Though he doesn't consider himself a hero, Mack is thankful that he knew what to do when the boy got caught in the rip current. But Mack says that the most important safety tip is to always swim near other people. Brewster agrees: "Understanding the phenomenon is very valuable and it very well may save your life," he says. "But the best advice is to pick a beach with lifeguards."

It's your Choice:

1 Over--percent of lifeguard rescues are due to distress caused by rip currents.

(A) 10

(B) 25

(C) 40

(D) 80

2 A rip current is a powerful flow of water that moves--shore.

(A) toward

(B) parallel to

(C) away from

(D) far from

3 Mack knew there was a break in the sandbar because

(A) waves weren't breaking there.

(B) the waves were taller there.

(C) he could see the ocean bottom.

(D) waves were plentiful there.

4 Rip currents are usually less than--wide.

(A) 2.5 m (8 ft)

(B) 3 m (10 ft)

(C) 15 m (50 ft)

(D) 30.5 m (100 ft)

5 Which of the following is good advice for someone who is caught in a rip current?

(A) Stay calm.

(B) Try to swim parallel to shore out of the rip current.

(C) If you can't escape the rip current, tread water until the current dies down.

(D) All of the above.

ANSWER

1. d 2. c 3. a 4. d 5. d

Nuts & Bolts

Rip currents form when conditions along a beach force a large amount of water to flow through a narrow passageway, such as a gap in a sand-bar or a deep channel along a pier. See how to escape these currents.