Rip Currents and How to Avoid Them

Wednesday - July 26 2023, 22:30 UTC - 1 year ago

Rip currents are powerful currents that flow from shore to sea at speeds of up to several feet per second, making them dangerous to beach-goers. There are two types of rip currents, bathymetric and transient, which are created by wave action. To stay safe, avoid beaches with lifeguards, pay attention to beach flags, and follow escape techniques such as floating and swimming parallel to the shore.

If you’ve ever waded into the ocean for a swim and suddenly realized that the shore is getting farther away, not closer, you may have encountered a rip current. Common at beaches worldwide, these powerful currents flow from the shore toward the sea at speeds up to several feet per second. It’s important to know what rip currents are and how to look for them, because they are a leading cause of drownings in the surf zone near shore. According to one recent estimate, rip currents have accounted for 435 drownings in the U.S. since 2017. National Weather Service offices that serve coastal communities issue forecasts that predict where and when rip currents are likely to occur. Those forecasts draw on decades of research into the physics of rip currents. Many scholars, including our research group, are finding innovative ways to discover more about rip currents – including their important roles in coastal marine ecosystems.

Not all rip currents are the same .

All rip currents have similar effects, but they can form in several ways. One type of rip, known as a bathymetric or channel rip current, forms when there are gaps between breaking waves. As waves break, they push water toward the beach and raise the level of the water slightly. If waves break on a sandbar, but not in a deeper channel that cuts through the sandbar, the extra water that the waves have pushed toward the beach escapes back to the ocean through the channel. The flow of the escaping water acts like a conveyor belt, moving water, unsuspecting swimmers and small marine organisms offshore. Another type, known as a transient or flash rip current, forms when surf is choppy. The edges of breaking waves push on the water and make it spin, like a fast ice skater bumping into someone. This creates whirls known as eddies, which can combine to form larger whirls, with currents that act like temporary conveyor belts. Flash rip currents are an active area of research.

Swim, float, call for help .

Choosing beaches with lifeguards and paying attention to beach flag warnings are the best ways to avoid rip currents. However, if you get caught in one, here are some techniques for getting safely back to shore. Think of a rip current as a swift river cutting through the surf away from the shore. Swimming against the current is going to tire you out and put you at risk of drowning. Instead, swim parallel to the beach – think of heading for the "river banks" – until you are out of the rip current’s pull. Once you’re no longer fighting it, you can swim back to shore. Another strategy is to float until the rip current carries you offshore beyond the breaking waves. Rip currents slow down here, so you can swim away from the rip current and back to shore. If you believe you’re in danger, try to stay calm. Wave your arms and call for help. If you see someone caught in a rip current, throw them a flotation device and alert a lifeguard.

Forecasting rip currents .

The National Oceanic and Atmospheric Administration’s rip current hazard model provides advance forecasts of the likelihood of encountering hazardous rip currents given wave conditions at specific beaches. NOAA work with local authorities to distribute those forecasts to the public.