Understanding The Ocean: Currents

by Tracy, June 6, 2017

Cabarete, Dominican Republic may be a small town, but it comes with a glowing reputation as one of the best watersports destinations on the planet. The warm, consistent trade winds have put Cabarete on the map and subsequently has hosted many prestigious watersports competitions including the World Kitesurfing League. As with any watersports destination, it’s important to know the area and have an understanding of the ocean. For this reason, we have created a series of articles under the title Understanding The Ocean. In this episode, we’ll be covering currents and how they affect us globally and ultimately locally. We will also discuss rip current safety.

Currents are a large movement of water in one direction and can be temporary or long-lasting, near the surface or in the depths of the ocean. The biggest of these currents shape the Earth’s global climate patterns and local weather conditions by moving heat around the world. These enormous currents, like a global conveyor belt, are mainly initiated by differences in temperature and salinity. This planetary current pattern slowly moves around the world, taking 1000 years to complete the circuit. It all begins in the Arctic when ice freezes and denser cold salty water is left behind and sinks towards the sea floor. It’s not only temperature and salinity that cause currents, wind also plays a significant role especially in surface currents. Once generated, the direction of the current comes from gravity and the Coriolis force (an apparent force that deflects moving objects as a result of the Earth’s rotation. In the northern hemisphere it deflects to the right and in the southern hemisphere to the left).

Just to add in another factor, there are two types of currents, surface currents, and deep-water currents. Surface currents consist of the first 1,300 feet of water and contain about 10% of the total volume of water in the oceans. Deep-water currents move the remaining 90% of the ocean, and this deep water is much colder than the surface with a much higher salt content.

Not all currents occur on such a grand scale. Individual beaches often have smaller currents including rip currents. Rip currents are narrow channels of water that form when waves of different intensities break on the shoreline and generate currents that keep the water level by pulling the large amounts of water brought in by the waves, back into the ocean. These currents can move faster than an Olympic swimmer at speeds of 2.4m per second, and as this moves away from shore, you can find yourself swept out very quickly.

Fortunately, rip currents can be spotted before entering the water and the main things to look for are:

  • Gaps between the waves – A small patch of calm water in an otherwise choppy sea may be inviting, but this is often a rip current sucking water back out to sea.
  • Discolored water – Rip currents tend to drag large amounts of sediment back out to sea, so if you notice a jet of discolored water, avoid that area.

When the water is shimmering and turquoise blue, we understand you may forget to check the signs so if you do get caught in a rip here’s what to do:

  • Stay calm – Rip currents pull you along the water and not under it, so it’s important not to panic and keep your head above water. Don’t waste precious energy trying to swim against the current, just stay calm and follow our next steps.
  • Swim parallel to the shore – The best way to escape a rip current is to swim perpendicular to it rather than against it. Since most rip currents are less than 80 feet wide, you can swim out of the side and return to the beach further along.
  • Go with the flow – This one sounds daunting, but rip currents stay close to the shore and often dissipate just beyond the breaking waves. So, remain calm, preserve your energy, float out with the current, and eventually the force will weaken so you can swim along and re-enter the beach at a different spot.

It’s important to look for the signs before entering the water, or, better yet, ask a local. Once you have an awareness of rip currents, you’ll notice some water users such as surfers use these current to help them get out to the waves. They’re not all bad, but every water user should understand the basics and potential dangers of currents.

If your thirst for knowledge hasn’t been quenched, learn more about the ocean in Part One of our series regarding waves and Part Two regarding tides.

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