Whirlpool

Have you ever pulled the plug from a bathtub full of water? Maybe you’ve done the same after washing dishes in the sink. If so, you probably noticed the water started to swirl around the container. It moved faster and faster above the drain. Eventually, it formed something that looked like a tornado.

Of course, it wasn’t a tornado. It was a whirlpool! These bodies of swirling water can form in nature, too. And they’re potentially dangerous for people, animals, and ships that get too close.

Whirlpool, rotary oceanic current, a large-scale eddy that is produced by the interaction of rising and falling tides. Similar currents that exhibit a central downdraft are termed vortexes and occur where coastal and bottom configurations provide narrow passages of considerable depth. Slightly different is vortex motion in streams; at certain stages of turbulent flow, rotating currents with central updrafts are formed. These are called kolks, or boils, and are readily visible on the surface.

Notable oceanic whirlpools include those of Garofalo (supposedly the Charybdis of ancient legend), along the coast of Calabria in southern Italy, and of Messina, in the strait between Sicily and peninsular Italy. The Maelstrom (from Dutch for “whirling stream”) located near the Lofoten Islands, off the coast of Norway, and whirlpools near the Hebrides and Orkney islands are also well known. A characteristic vortex occurs in the Naruto Strait, which connects the Inland Sea (of Japan) and the Pacific Ocean.

Are whirlpools natural?

Powerful ones are often referred to as maelstroms and are mainly common in seas and oceans. Smaller whirlpools are common at the base of waterfalls and can also be observed in man-made structures such as dams and weirs. In oceans, they are mainly caused by tides and are capable of submerging large ships.

How strong is a whirlpool?

When the moon is full and the difference between high and low tide is at its greatest (usually in March), the whirlpool at Saltstraumen, near Bodø in Norway, is the strongest in the world. At its height of its powers, the currents here reach 20 knots