Menus Subscribe Search

Follow us


Warning signs mark a dangerous shore break and rip current along the north shore of Oahu, Hawaii. (PHOTO: JOSHUA RAINEY PHOTOGRAPHY/SHUTTERSTOCK)

Warning signs mark a dangerous shore break and rip current along the north shore of Oahu, Hawaii. (PHOTO: JOSHUA RAINEY PHOTOGRAPHY/SHUTTERSTOCK)

Deadlier Than a Hurricane

• February 08, 2013 • 4:00 AM

Warning signs mark a dangerous shore break and rip current along the north shore of Oahu, Hawaii. (PHOTO: JOSHUA RAINEY PHOTOGRAPHY/SHUTTERSTOCK)

How the science of rip current prediction could save lives

On a late summer afternoon off the North Carolina coast, a young graduate student in civil engineering waded into a scary first-person experiment. Tuba Ozkan-Haller was the daughter of an admiral in the Turkish navy, but despite that oceanic upbringing, “I was always very tentative and extremely afraid of the water,” she says. “My poor dad was always frustrated.” As she grew up she found that the more she learned about the ocean, the less afraid she was.

“I felt like I had more control.”

On this partly cloudy afternoon she stepped into the surf—the waves weren’t very big—and side-stepped towards a rip current she had spotted from the shore. The current pulled her feet out from underneath her. This was show time. She knew to stay afloat and just enjoy the ride—she was doing this on purpose, after all—but she couldn’t help but get a bit disoriented, a bit terrified.

A few minutes later, and more than two hundred yards from the shore, the rip current let her go.

In an average year, rip currents just like the one in Ozkan-Haller’s experiment kill more Americans—from first-time ocean goers to experienced swimmers—than do hurricanes. Caught off guard, people are swept out to sea, where they tire themselves out swimming against the pull of the current, which can flow nearly as fast as Michael Phelps swims the 100-meter butterfly.

 

While shark attacks and tsunamis make headlines, rips account for 80 percent of all rescues performed by lifeguards in the United States. The combination of fear, panic, and exhaustion kills more than 100 people each year. Surfers, lifeguards, and experienced ocean-goers can usually spot a rip current relatively easily—they look for sandy, discolored water extending seaward, or a choppy stretch of ocean, generally about 10 yards wide, where the waves are lower than on either side.

[SlideDeck2 id=52475]

(Photos courtesy University of Delaware Sea Grant College Program)

They can avoid the current, use it as an expressway to better waves, or swim away from it by paralleling the coast.

But those instincts can be lacking for many splashing around in the surf, and if swimmers knew where the currents were located, they could better avoid the danger in the first place.

Enter Tuba Ozkan-Haller, now an associate professor at Oregon State University, who for the last five years has been working to develop a model to identify the location of rip currents up to a day in advance.

She does this by surveying the topography of the ocean floor to figure out how waves will travel over it; this then allows her to see how that mass of water can escape back from shore via a rip current. Ozkan-Haller takes all these factors and plugs them into a mathematical model she developed that predicts where and when rip currents will occur and how strong they will be.

Helping her efforts are cutting-edge surveying technologies that allow her to observe properties at the water’s surface and infer the underlying bathymetry from those observations. This is a much more efficient and accurate way to get a sense of the sea floor than the standard procedure of surveying from a boat.

“I’m totally floored by how well we can do compared to traditional surveying methods,” says Ozkan-Haller. “You can set up a radar system near a beach and get continuous estimates of the bathymetry as it evolves from day to day without ever stepping foot into the water.”

Trying to forecast rip currents is nothing new, and Ozkan-Haller is part of a lively research community studying, and perhaps forecasting, rips in the U.S. and around the world. Twenty years ago, Jim Lushine of the National Weather Service found that he could reliably predict rip current intensity by comparing lifeguard rescues to weather conditions and seeing which ones influenced rescues.

“Many National Weather Service offices presently give rip current ‘outlooks,’” says Chris Brewster, president of the United States Lifesaving Association. This is a “term they use for predictions that are not full predictions.”

Ozkan-Haller points out that the NWS forecasts the probability of occurrence, while she is running a predictive model, the way a weatherman predicts a storm.

“The kind of monitoring and prediction system that I’m dreaming up does not exist anywhere in the U.S.,” says Ozkan-Haller.

Although lifeguards are highly trained at spotting rip currents in the water, an accurate, daily prediction could be a big help. A lifeguard agency could increase staffing on days when rips were predicted, says Brewster. But, he says, in the same way fire departments may staff up during periods of high fire danger, it’s not something done on a regular basis, because each day they need to be ready for anything.

“I don’t know that every single beach along our coast needs this system,” Ozkan-Haller says, “but it feels like there’s a handful to start with that would benefit from this kind of technology.” She sees a scenario where lifeguards could record data and report to her on how accurate her predictive modeling was working.

Other applications of Ozkan-Haller’s predictive system range from the monitoring of pollutants flowing out to sea after a storm, to the transport of animal larvae that’s been spawned in the shallow waters and needs to be carried back off shore.

Still, the most exciting application is saving lives and helping people, like her, to be just a little bit less afraid of the ocean.

Matt Skenazy
Matt Skenazy, an assistant editor at Outside magazine, is a former Pacific Standard fellow. His articles have appeared in Sierra, Men’s Journal, the Surfer’s Journal, and Climbing, among others publications.

More From Matt Skenazy

A weekly roundup of the best of Pacific Standard and PSmag.com, delivered straight to your inbox.

Recent Posts

November 26 • 4:00 PM

Turmoil at JPMorgan

Examiners are reportedly blocked from doing their job as “London Whale” trades blow up.


November 26 • 2:00 PM

Rich Kids Are More Likely to Be Working for Dad

Nepotism is alive and well, especially for the well-off.


November 26 • 12:00 PM

How Do You Make a Living, Taxidermist?

Taxidermist Katie Innamorato talks to Noah Davis about learning her craft, seeing it become trendy, and the going-rate for a “Moss Fox.”


November 26 • 10:28 AM

Attitudes About Race Affect Actions, Even When They Don’t

Tiny effects of attitudes on individuals’ actions pile up quickly.


November 26 • 10:13 AM

Honeybees Touring America


November 26 • 10:00 AM

Understanding Money

In How to Speak Money, John Lanchester explains how the monied people talk about their mountains of cash.


November 26 • 8:00 AM

The Exponential Benefits of Eating Less

Eating less food—whole food and junk food, meat and plants, organic and conventional, GMO and non-GMO—would do a lot more than just better our personal health.


November 26 • 6:00 AM

The Incorruptible Bodies of Saints

Their figures were helped along by embalming, but, somehow, everyone forgot that part.


November 26 • 4:00 AM

The Geography of Real Estate Markets Is Shifting Under Our Feet

Policies aimed at unleashing supply in order to make housing more affordable are relying on outdated models.



November 25 • 4:00 PM

Is the Federal Reserve Bank of New York Doing Enough to Monitor Wall Street?

Bank President William Dudley says supervision is stronger than ever, but Democratic senators are unconvinced: “You need to fix it, Mr. Dudley, or we need to get someone who will.”


November 25 • 3:30 PM

Cultural Activities Help Seniors Retain Health Literacy

New research finds a link between the ability to process health-related information and regular attendance at movies, plays, and concerts.


November 25 • 12:00 PM

Why Did Doctors Stop Giving Women Orgasms?

You can thank the rise of the vibrator for that, according to technology historian Rachel Maines.


November 25 • 10:08 AM

Geography, Race, and LOLs

The online lexicon spreads through racial and ethnic groups as much as it does through geography and other traditional linguistic measures.


November 25 • 10:00 AM

If It’s Yellow, Seriously, Let It Mellow

If you actually care about water and the future of the species, you’ll think twice about flushing.


November 25 • 8:00 AM

Sometimes You Should Just Say No to Surgery

The introduction of national thyroid cancer screening in South Korea led to a 15-fold increase in diagnoses and a corresponding explosion of operations—but no difference in mortality rates. This is a prime example of over-diagnosis that’s contributing to bloated health care costs.



November 25 • 6:00 AM

The Long War Between Highbrow and Lowbrow

Despise The Avengers? Loathe the snobs who despise The Avengers? You’re not the first.


November 25 • 4:00 AM

Are Women More Open to Sex Than They Admit?

New research questions the conventional wisdom that men overestimate women’s level of sexual interest in them.


November 25 • 2:00 AM

The Geography of Innovation, or, Why Almost All Japanese People Hate Root Beer

Innovation is not a product of population density, but of something else entirely.


November 24 • 4:00 PM

Federal Reserve Announces Sweeping Review of Its Big Bank Oversight

The Federal Reserve Board wants to look at whether the views of examiners are being heard by higher-ups.



November 24 • 2:00 PM

That Catcalling Video Is a Reminder of Why Research Methods Are So Important

If your methods aren’t sound then neither are your findings.


November 24 • 12:00 PM

Yes, Republicans Can Still Win the White House

If the economy in 2016 is where it was in 2012 or better, Democrats will likely retain the White House. If not, well….


November 24 • 11:36 AM

Feeling—Not Being—Wealthy Cuts Support for Economic Redistribution

A new study suggests it’s relative wealth that leads people to oppose taxing the rich and giving to the poor.


Follow us


Attitudes About Race Affect Actions, Even When They Don’t

Tiny effects of attitudes on individuals' actions pile up quickly.

Geography, Race, and LOLs

The online lexicon spreads through racial and ethnic groups as much as it does through geography and other traditional linguistic measures.

Feeling—Not Being—Wealthy Cuts Support for Economic Redistribution

A new study suggests it's relative wealth that leads people to oppose taxing the rich and giving to the poor.

Sufferers of Social Anxiety Disorder, Your Friends Like You

The first study of friends' perceptions suggest they know something's off with their pals but like them just the same.

Standing Up for My Group by Kicking Yours

Members of a minority ethnic group are less likely to express support for gay equality if they believe their own group suffers from discrimination.

The Big One

One in two United States senators and two in five House members who left office between 1998 and 2004 became lobbyists. November/December 2014

Copyright © 2014 by Pacific Standard and The Miller-McCune Center for Research, Media, and Public Policy. All Rights Reserved.