With summer just around the corner, more and more Americans are headed to the beach, where the often unknown dangers of rip currents lurk just below the surface of the ocean.
While these common phenomena may not look like much from the sand, they can be deadly — especially if swimmers don't know how to handle them.
An estimated 100 people are killed by rip currents each year, and rip currents account for more than 80 percent of rescues performed by surf beach lifeguards, according to the United States Lifesaving Association.
Here's what to know about rip currents, and how you can stay safe if you ever find yourself stuck in one.
What exactly is a rip current?
Rip currents are fast-moving, narrow channels of water that can move as quickly as eight feet per second, according to the National Oceanic and Atmospheric Administration's National Ocean Service.
They're found along the East, Gulf and West coasts of the U.S. and also along the shores of the Great Lakes, flowing away from the shoreline and toward the ocean, either perpendicular or at an acute angle to the shoreline, NOAA says.
Rip currents can happen on any beach where waves are breaking, and form when waves travel from deep to shallow water, often along low spots of breaks in sandbars, or near structures like docks and piers. They're different from rip tides, as tides move up and down, while currents move horizontally, according to Dr. Greg Dusek, National Ocean Service Senior Scientist.
It's a misconception that rip currents will drag swimmers under the water — what they actually do is pull swimmers away from shore, often prompting a panicked response.
Why are they so dangerous?
That panicked response is often what dooms swimmers who find themselves caught in a rip current — in their desperation to fight the current and escape back to shore, they tire themselves out quickly and drown. Even strong swimmers can be swept out extremely quickly.
Dusek calls rip currents "a huge public safety risk," and also strongly advises against rushing into the water to save someone who appears to be caught in one.
"Often the person that goes in to make the rescue ends up being the one who drowns," he says in a 2018 rip current safety webinar.
What should you do if you're stuck in a rip current?
If you find yourself caught in a rip current, the first step is to remain calm and avoid trying to fight through it.
"The most important thing to remember if you are ever caught in a rip current is not to panic," NOAA says. "Continue to breathe, try to keep your head above water, and don't exhaust yourself fighting against the force of the current."
Dusek offers similar advice, advising swimmers to relax and stay calm, as the current will not pull you under water, just away from shore.
"If you feel like you can swim out of it, swim along the shore until you feel like you're out of the current, and then follow the waves back to shore at an angle, away from the rip," he says. "If you're not sure if you can swim out of the rip, you want to float and then wave your arms and call for help."
NOAA says the best option is swim parallel to shore instead of toward it, as most rip currents are less than 80 feet wide, but if that's not feasible, you can let the current carry you out to sea until its force has weakened. At that point, you can swim back to shore without having to fight it.
If you see someone who is stuck in a current, jumping into the water to help will only put yourself in danger. If that happens, you should remain onshore and yell for a lifeguard, or throw the person something they can float on and try to guide them to safety, Dusek says.
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How can I avoid rip currents?
The best way to avoid a rip current is to check weather conditions before you head to the beach, and make sure you're only swimming when there's a lifeguard present, according to the National Weather Service.
Dusek also advises staying away from man-made structures in the water, as they focus "wave energy and can effectively create an almost permanent rip current there."
Indicators that there is a rip current present include foam and sediment and discolored water extending away from shore, or flat spots in the lines of breaking waves, according to Dusek.
Other clues include a narrow gap of darker water between areas of breaking waves that seems calm, a channel of churning, choppy water, a difference in water color and a line of foam, seaweed or debris moving out to sea, according to the United States Lifesaving Association.