Vietnam Backpack Travel Guide – A rip current, commonly referred to simply as a rip, or by the misnomer “rip tide”, is one specific kind of water current that can be found near beaches. It is a strong, localized, and rather narrow current of water. It is strongest near the surface of the water, and it moves directly away from the shore, cutting through the lines of breaking waves.
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Rip currents can occur at any beach where there are breaking waves: on oceans, seas, and large lakes. The location of rip currents can be unpredictable: while some tend to reoccur always in the same place, others can appear and disappear suddenly at various locations near the beach.
A rip current forms because breaking waves push water towards the land. Water that has been pushed up near the beach flows together (as feeder currents), and this water finds a place where it can flow back out to sea. The water then flows out at a right angle to the beach in a tight current called the “neck” of the rip, where the flow is most rapid. When the water in the rip current reaches outside of the lines of breaking waves, the flow loses power, and dissipates in what is known as the “head” of the rip. Sometimes tendrils of left-over current then actually curve back towards the shore.
Rip currents can be hazardous to people who are in the water. Swimmers or floaters who are caught in a rip and who do not understand what is going on, may not have the necessary water skills, may panic, or may exhaust themselves by trying to swim directly against the flow of water. Because of these factors, rips are the leading cause of rescues by lifeguards at beaches, and in the US rips are responsible for an average of 46 deaths from drowning each year.
A rip current is not the same thing as undertow, although some people use the latter term when they mean a rip current. Contrary to popular belief, neither rip nor undertow can pull a person vertically down and hold them under the water surface; A rip simply carries floating objects, including people, to an area outside the zone of the breaking waves.
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Rip currents are a potential source of danger for people who are in shallow water with breaking waves in seas, oceans and lakes. Rip currents are the cause of 80% of the rescues carried out by beach lifeguards.
Rip currents typically flow at 0.5 metres per second (1–2 feet per second), but they can be as fast as 2.5 metres per second (8 feet per second), which is faster than any human can swim. However, most rip current are fairly narrow, and even the widest rip currents are not very wide; swimmers can easily exit the rip by swimming just a few strokes at a right angle to the flow, parallel to the beach. Swimmers who are unaware of this fact may exhaust themselves trying unsuccessfully to swim against the flow. The pull of the current also fades out completely at the head of the rip, outside the zone of the breaking waves, so there is a definite limit to how far the swimmer will be taken out to sea by the flow of a rip current.
In a rip current, death by drowning occurs when a person has limited water skills, or panics, or persists in trying to swim to shore against a strong rip current, thus eventually becoming exhausted.
According to NOAA, over a 10-year average, rip currents cause 46 deaths annually in the United States, and 64 people died in rip currents in 2013. However, the The United States Lifesaving Association “estimates that the annual number of deaths due to rip currents on our nation’s beaches exceeds 100.
Recognizing and identifying rips
Rip currents have a characteristic appearance, and this means that with practice, and using careful observation, lifeguards, beach goers, and water users can learn to notice and identify rips, thus generally being able to avoid them. Rip currents often look almost like a road or a river running out to sea, away from the shore. Rip currents are easiest to notice and identify when the zone of breaking waves is viewed from a high vantage point. Beachgoers can also talk to lifeguards, who are always watching for rip currents, and who will move their safety flags so that swimmers can avoid rips. The following are some characteristics that a person can use to visually identify a rip before entering the water:
- There is a noticeable break in the pattern of the waves: the water often looks flat where the rip is, in contrast to the lines of breaking waves on either side of the rip.
- A “river” of foam: the surface of the rip often looks foamy, because the water is churned up.
- Different color: the rip usually differs in color from the surrounding water; it is often more opaque, cloudier, or muddier, and so, depending on the angle of the sun, the rip may show as darker or lighter than the surrounding water.
- It is sometimes possible to see that foam or floating debris on the surface of the rip is moving out, away from the shore. In contrast, in the areas of breaking waves, floating objects are being pushed towards the shore.
These characteristics are helpful in learning to recognize and understand the nature of rip currents so that a person can recognize the presence of rips before entering the water. In the US, some beaches have signs created by NOAA and USLA, explaining what a rip current is and how to escape one. These signs are entitled, “Rip Currents; Break the Grip of the Rip”.