Summer officially begins Friday and that means more people will start spending time at the beach.
But if you've ever soaked up the sun and sand, you've probably seen a scary sign telling you to watch out for rip currents. Rip currents are a real danger for beachgoers: The U.S. Lifesaving Association estimates more than 100 people are killed by rip currents every year, and lifeguards rescue at least 30,000 swimmers a year from rip currents.
But what are rip currents? Why are they so dangerous? Why should you avoid your gut instinct if you get caught in one?
Here's what to know before heading to the beach this summer.
What are rip currents?
You might have heard of rip currents by the common misnomer "rip tides." They are actually two different things, according to the National Ocean Service.
A rip tide is a specific type of current associated with the swift movement of tidal water through inlets and the mouths of rivers and harbors.
Rip currents occur in bodies of water with breaking waves; they are channels of water that flow at a faster pace than the surrounding area. Swimmers who are caught in rip currents can get sucked away at speeds of up to 8 feet per second, far too fast for many swimmers to make it safely back to shore.
The National Weather Service and other websites post warnings about high chances of rip currents, so swimmers almost always have ample warning that rip currents are possible or are occurring.
What should I do if I get caught in one?
First, don't panic – there is a way out.
Remain calm and swim parallel to the shoreline, which is perpendicular to the current. Or just go with the flow and ride out the rip current, saving your energy for the swim back to shore.
Don’t become a victim by trying to save someone. If you see someone caught in a rip current, get help from a lifeguard, if available. Call 911 for further assistance.
Falk Feddersen, professor of physical oceanography at Scripps Institution of Oceanography in San Diego, told USA TODAY that when people are not strong swimmers, they tend to panic and try to swim against the current, which results in exhaustion and drowning.
He recommended simply bobbing with the water until you make it back to shore or you are away from the active parts of the rip current.
"Once you’re away from the active current, you can swim back to shore," he said.
Why are rip currents so dangerous?
To get an idea of how dangerous a rip current can be, you only need to look at the many deaths or near-deaths over the years.
A California high school football player drowned in a rip current while boogie boarding at Half Moon Bay in April. In July 2017, at least 30 people formed a human chain to rescue nine people from a rip current in Lake Michigan. A tourist died after saving a Michigan mayor caught in a rip current in the Caribbean in March 2015.
A 2014 study by the University of New South Wales says that the rapid expelling of energy – which can be caused by panicking or swimming to the shore – often leads to drowning.
"Energy should be conserved wherever possible," wrote Rob Brander, author of the study.
Feddersen explained that it's unlikely that a rip current will pull you out to sea.
He added that once you have knowledge of rip currents and how to deal with them, they can be a "beautiful, cool and fun" feature to a beach vacation.
Follow Elinor Aspegren on Twitter: @elinoraspegren.
This article originally appeared on USA TODAY: A rip current at the beach can be deadly, but experts say you can escape by doing this