Science And Environment: How Rip Currents Work

How to survive rip tides and undertows: By learning how rip currents form, swimmers can survive dangerous ocean waves and prevent drowning.

Rip currents, also popularly known as rip tides or undertows, are one of the major causes of sea side drowning. With the proper information, rip currents are not only identifiable, but survivable, yet many swimmers are not familiar with the conditions that create rip currents, nor the techniques necessary to escape them.

Rip currents form when heavy, continuous, breaking waves push a larger than usual volume of water up toward the shoreline, water which must eventually recede back toward the ocean. The action of these swelling waves often create underwater sandbars which eventually collapse, allowing gravity to suddenly pull that large volume of shore-side water toward the sea in a tight, narrow, river-like configuration. Sometimes larger sandbars contribute to the production of a basin effect, where stronger waves actually crest over the sandbar and create a pool of water between the shore and the sandbar. At some point all this water will find a way to return to the sea, either by traveling along the shore until it finds a weak point to break through, or by rocking back against the sandbar as the water in the basin or pool recedes. The rip current actually works like a conduit, running water in a perpendicular line from the shore to the deeper parts of the ocean. While rip currents are not generally wider than 50 feet, they can be fast and long, pulling an unsuspecting swimmer as far as 2000 feet toward the sea. Rip currents are not relegated to the oceans alone; they can form at the Great Lakes as well.

Rip currents will occur more frequently under certain conditions. Off shore storms can contribute to continuous wave activity, one reason rip currents often form during hurricane and tropical storm season. Strong winds can contribute to the swell. Rip currents also form around piers and jetties. Sometimes they can be identified by their muddy color or by a sudden disturbance in the water which seems to be pulling seaweed or other flotsam out toward the ocean.

While it takes windy or turbulent seas to create a rip current, once the rip current forms, the water there can appear deceptively calm, luring swimmers toward it. Too often inexperienced swimmers take that area of calm as a safer place to swim. Rip currents can travel at strong speeds, some as fast as five mph. Swimmers panic when they see how far they have been pulled from the shore. It is the worst thing they can do.

Swimmers caught in a rip current generally attempt to fight it and swim against it, toward shore. This is a fatal mistake. Even strong swimmers cannot fight the power of a rip current. Experienced swimmers and surfers know that the only way to survive a rip current is to ride it out.

A rip current will be strongest at the point of rupture, the break in the sandbar, but as it fans out, it loses power and speed. If a swimmer is in relatively shallow waters, but feels the current dragging him backward, he should try to walk out of the current by walking parallel to the shore, allowing incoming waves to gradually press him toward the shore. If the swimmer is already in deeper water and cannot reach bottom, he must float with the current until he feels it dissipate. Once out of the rip current, the swimmer should begin to swim toward the shore in a diagonal manner, until the water is shallow enough for him to stand and walk in.

Rip currents are responsible for the deaths of swimmers each year. Weak swimmers should avoid deep waters: Most swimmers caught in rip currents are in waters only up to their chests. The idea that a swimmer is safe so long as he can touch the ocean bottom is a dangerously false belief. For surfers and strong swimmers, rip currents are manageable, but even strong swimmers have been fooled by their confidence, by underestimating the strength of rip currents. All swimmers should watch the ocean for signs of rip currents, and all swimmers should avoid areas with warning flags or signs indicating unsafe waters. So long as a swimmer respects the power of ocean waters, his time at the beach will be safe and enjoyable.

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