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More than 100 drownings occur each year in the United States due to rip currents. In Florida, more people are killed annually by rip currents than hurricanes, tornadoes and sharks,combined. Lifeguards certainly know that 80 percent of water rescues on ocean beaches are associated with rip currents. Increased knowledge of rip current processes on high-energy Atlantic beaches can prevent drownings. Make it your responsibility to be informed, for your life and others.
Rip currents are strong, narrow currents extending from shore to distances of hundreds of feet offshore, sometimes a quarter mile. They occur on beaches when moderate to large waves continually pile up water as the waves break on shore. The excess water returns to sea via the simple process of gravity but it occurs within narrow “squirts” that generally range from 20 to 100 feet wide and possess offshore-oriented currents of three to eight feet per second.
Rips typically extend from the shoreline, through the surf zone and past the offshore line of breakers. They are not generated in the absence of breaking waves.
Steep beach profiles are more likely to generate strong rip currents than near-horizontal beaches. In rip-prone areas, these energetic features can occur frequently although their position may vary according to incident wave direction, alongshore currents and winds. Although rip currents are not caused by tides, water level at the beach can impact rip current generation and intensity, with rip current velocities often increasing as water level decreases.
Undoubtedly, the strongest rip currents are generated by large waves that have long wavelengths (distance between crests). Under such conditions, all swimmers should beware before entering the water. Look for dips in the alongshore sand profile as rip currents often originate in these natural, offshore channels. They also may be ephemeral, forming quickly and lasting a few hours or sometimes days before dissipating.
With practice, anyone can become skilled at spotting rip currents; the higher the vantage point the better. Look for a line of foam, weed or surface debris moving outward from shore. It may be associated with a difference in water color and/or a choppy area situated between incoming, breaking waves.
Rip currents cause horizontal flow only. They do not cause “undertow”. Conversely, when waves break on the beach, the offshore return flow occurs at the seafloor, sometimes causing a standing person to lose his/her footing – thus the perilous description of being towed under.
If a swimmer is suddenly swept offshore by a rip current, all he/she needs to do is swim parallel to shore for 20 to 50 feet in either direction and the crisis will be averted. Note that even the strongest of Olympic swimmers are unable to swim against a rip current but an average beachgoer can easily swim perpendicular to, and out of the narrow, offshore current. When out of the rip, the swimmer should wave to people on the beach that he/she is safe, then swim to shore at a comfortable pace, unopposed by the offshore flow a short distance away.
Drownings from rip currents occur when a swimmer is carried offshore, becomes fatigued and incapable of staying afloat. Swimmers are not pulled beneath the surface by rip currents, even far offshore. The combination of swimmer exhaustion and panic give rise to drowning, often within 200 feet of shore and in sight of terrified onlookers.
If ocean swimmers are educated about rip currents, in-water panic can be eliminated. Understanding the need to swim perpendicular to the offshore current is a simple solution for swimmers of all skill levels. Educate people who are about to enter the surf when you visit the beach on rough days. You may save their life by doing so.
The United States Lifesaving Association, in partnership with NOAA’s National Weather Service and National Sea Grant Program, is raising awareness of the dangers of rip currents.
Additionally, the Weather Service issues a Surf Zone Forecast in many beach areas for prediction of wave strength and a Rip Current Outlook to advise swimmers of risk on area beaches.
Scott E. McDowell has a doctorate degree in ocean physics, is a licensed captain and author of Marinas: a Complete Guide available at www.scottemcdowell.com. Contact him at firstname.lastname@example.org.