Study Aims To Better Predict Deadly Rip Currents

Aug 20, 2012

New research this fall will try to find a better way to predict dangerous currents in the Great Lakes. The number of deaths attributed to rip currents has been rising each of the last few summers.

Using Doppler
The experiment will see if Doppler radar can predict rip currents. That’s the same technology that can look at how the air moves inside fast developing storms.

“We’re doing the same thing, a Doppler radar looks at the water surface and records the actual presence of the currents,” says Guy Meadows with the Great Lakes Research Center at Michigan Technological University.

Along with radar devices at the shore, small robots that look like miniature torpedoes will run through the surf to map rip currents.

The idea is to improve forecasting for the National Weather Service, Meadows says.

“The question is what makes one section of beach susceptible to rips and then a mile away not. And what conditions trigger those events.” 

In a Few Locations
The devices will be tested next month at Holland and Grand Haven State Parks.  

Those are places with piers in the water and when the wind is out of a certain direction rip currents build up along those piers. That’s when park managers put up red flags on the beaches to warn swimmers.

Joyce Rhodes is supervisor at Grand Haven State Park this year. Before that, she managed the park in Holland for fourteen years.

“And at one point last year we had to close Holland State Park because the rip currents were so bad and the waves were so bad and people wouldn’t stay out of the water,” she says.

The last couple of years there have been several close calls at Holland and Grand Haven when people have had to be rescued in strong surf but no drowning.

Rhodes says better information to predict rip currents will save lives. That is, if the information gets to people and they heed the warnings.

“A lot of them look for the red flag days because that’s the most fun in the water,” Rhodes says.

Deadly Weekend
A few weekends ago was the deadliest of the summer with seven drowning deaths in the Great Lakes, most attributed to heavy waves and strong rip currents.

The National Weather Service accurately predicted conditions that would produce the currents. But that didn’t prevent people from going in the water.

There was a drowning in Sleeping Bear Dunes National Lakeshore and at St. Joseph beach and several close calls on the same day.

Jim Keysor is a meteorologist with the weather service in Gaylord that covers much of the northern Lake Michigan shoreline. He says if the Doppler radar works to predict rip currents it will be a huge leap forward in forecasting.

“Right now we’re based on just looking broadly at some conditions that are favorable. And I think this has the potential to eventually maybe fine tune the locations of where they’re going to occur, maybe shortly before they do occur,” Keysor says.

Unusual for Great Lakes
Rip currents have not usually been associated with the Great Lakes. They’re more common in the oceans where waves roll in a more regular pattern.

Guy Meadows with the Great Lakes Research Center says the wave patterns in the lakes are more confused and erratic. And that can make rip currents deceptive. In fact, he says, on a big wave day on Lake Michigan for example people may actually choose a spot where a current is.

“Since rips are flows going out against the incoming waves, the wave field actually to the eye looks less intense at a particular location where the rip is,” Meadows says.

Right now, researchers have funding from the National Oceanic and Atmospheric Administration to test the radar devices and gather some data that may help better predict the currents. There’s no money for the devices to be placed at beaches on a regular basis.