Whirlpools 101: how they form, are they dangerous, and how to survive one

Whirlpools are menacing vortices that have the potential to draw things around them into a spiral of water. But, are they actually dangerous?
Christopher McFadden
A whirlpool near Saint-Malo in Brittany, France.
A whirlpool near Saint-Malo in Brittany, France.

olrat/iStock 

  • Whirlpools and maelstroms are essentially the same things except for differing sizes and power.
  • The vast majority of them are completely safe if you know what to do.
  • Larger, hundred-mile radius maelstroms, called eddies, appear to be critical for regional and global climates.

Whirlpools and maelstroms are strong natural phenomena that have long filled sailors with dread. Both are powerful rotating currents that form when the weather and other current-related factors align to form the perfect conditions to create them.

Long-feared by sailors and swimmers worldwide, most are completely safe if you avoid them altogether. But what exactly are they? And how do they form? Let's take a look.

What are whirlpools?

A whirlpool is a rotating body of water that occurs when two currents meet or one current hit a wall. For example, little whirlpools can develop at the plughole when a bath or sink drains.

Whirlpools can emerge in various sizes depending on the amount of water and the intensity of the interacting waves. They can also develop at the base of waterfalls and artificial structures like dams.

The majority of these phenomena are usually not dangerous. However, certain whirlpools can be extremely strong and hazardous. A maelstrom is described as a whirlpool that is especially "large, forceful, or violent." The tides are primarily responsible for maelstrom formation in the ocean along narrow straights.

Technically speaking, the correct phrase for a whirlpool with a downdraft is a vortex.

Whirlpools 101: how they form, are they dangerous, and how to survive one
Whirlpools of the maelstrom of Saltstraumen, Nordland, Norway.

Tides frequently generate whirlpools in maritime straits with narrow channels and swiftly moving water. Even though only small boats are in danger, there are stories of craft getting pulled into a "whirlpool."

Smaller whirlpools can be seen downstream of artificial structures like weirs, dams, and near river rapids. Large cascades, like Niagara Falls, can also create strong whirlpools.

According to the Niagra Parks website, some whirlpools grow and vanish over a short period of time, while other water systems maintain whirlpools for centuries. Maelstroms are the more powerful and hazardous whirlpools. These could fatally engulf anybody who gets too close.

Underwater whirlpools, known as deep eddies, are produced by ocean currents flowing around features like seamounts (submerged mountains). These do not affect surface ships but can be a hazard to underwater navigation. In 2014, Chinese Submarine 372 was caught by an eddie and began plunging unexpectedly into an ocean trench, only saving itself through rapid action on the part of the crew.

Some notable examples around the world are as follows:

1. The Saltstraumen maestrom, Norway is a very impressive one

Whirlpools 101: how they form, are they dangerous, and how to survive one
The tidal current at Saltstraumen, near Bodø, Norway,

A small strait known as Saltstraumen, can be found 20 miles (33 kilometers) southeast of Bodø, Norway, and is not far from the Arctic Circle. It has one of the world's strongest tidal currents, and when the current is strongest, whirlpools up to 33 feet (10 meters) in diameter and 16 feet (5 meters) in depth can develop.

2. Moskstraumen is another powerful maelstrom that can be found in Norway

Whirlpools 101: how they form, are they dangerous, and how to survive one
The maelstrom off Norway, as illustrated by Olaus Magnus on the Carta Marina, 1539.

The Moskstraumen or Moskenstraumen system of whirlpools can be found near the Lofoten Islands, off Norway's coast.

With flow currents reaching rates of up to 20 mph (32 kph), it is claimed as the second-strongest whirlpool on the entire planet. According to legend, this is the whirlpool that is marked as "Horrenda Caribdis" on Olaus Magnus's map. It also features in Jules Verne’s Twenty Thousand Leagues Under the Sea and is mentioned by Captain Ahab in Herman Melville’s Moby-Dick. The Moskstraumen comprises strong semi-daily tides, an oddly shaped seabed, and a shallow ridge between the Moskenesya and Vaery islands that makes the tides stronger and swirl around.

The Moskstraumen is a group of currents and crosscurrents that move at 11 mph (18 kph) and are described by Edgar Allan Poe, Jules Verne, and Cixin Liu as a huge, circular vortex that goes all the way to the ocean floor. In his short story "A Descent into the Maelstrom," published in 1841, Poe used the term "maelstrom" for the first time in English. Maelstrom" in 1841. In this tale about the Lofoten Maelstrom, two fishermen are sucked into the maelstrom while one escapes.

3. Scotland has its own famous whirlpool too

Whirlpools 101: how they form, are they dangerous, and how to survive one
A Corryvreckan whirlpool.

The Gulf of Corryvreckan is a narrow strait between the islands of Jura and Scarba, in Argyll and Bute, along Scotland's northern coast. A place of outstanding natural beauty, it is also home to the world's third-largest whirlpool.

The whirlpool is affected by a large rock pinnacle or wall under the sea, which rises to around 95 feet below the surface. Water is forced upward when it hits the rock, causing huge, swirling waves. The waters of Corryvreckan can be driven to waves of more than 30 feet (9 meters) by flood tides and input from the Firth of Lorne to the west. The noise of the accompanying maelstrom, which reaches speeds of 11 mph (18 kph), can be heard more than 10 miles (16 km) away.

A mannequin outfitted with a depth gauge and a high-visibility vest was once thrown into the Corryvreckan ("the Hag") by a documentary crew from the independent Scottish filmmakers Northlight Productions. A depth gauge value of 860 ft (262 m) indicates that the mannequin was destroyed and spewed up deep downstream. It also shows signs of being dragged along the bottom for a considerable distance.

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4. Other examples of whirlpools around the world

Whirlpools 101: how they form, are they dangerous, and how to survive one
Naruto whirlpools.

Between Deer Island, New Brunswick, Canada, and Moose Island, Eastport, Maine, USA, you can find the Old Sow Whirlpool. When the vortex is at its ferocious peak, it emits a screeching scream and can reach speeds of up to 17.1 mph (27.6 kph), earning it its name. "Piglets" are the names for the tiny whirlpools that surround this Old Sow.

The Naruto whirlpools, which attain speeds of 16 mph (26 kph), are found in the Naruto Strait close to Awaji Island in Japan. On Canada's Sunshine Coast, Skookumchuck Narrows is a tidal rapid where the current may reach speeds of over 19 mph (30 kph) and create whirlpools.

The northernmost portion of New Zealand's South Island is separated by the perilous French Pass (Te Aumiti). Over the years, the whirlpools that form in this area have claimed many lives after divers succumbed to the currents.

Are whirlpools dangerous and can you escape them?

Contrary to popular belief, and as often portrayed in fiction, like the whirlpool battle in "Pirates of the Caribbean", whirlpools aren't as destructive as they are depicted. Howeverul enoughful enough, they can pose a potential threat to people and small vessels.

That being said, most individuals who go near a whirlpool won't be caught up in a vortex, but many others, like kayakers, will find it helpful to know how to survive one.

Ken Whiting, a world-champion kayaker, advises that when entering the water, you should wear safety equipment such as a life vest and helmet. These can shield you from the battering currents that whirlpools are surrounded by. It is best to stay out of the area entirely if you spot any whirlpool warning signs.

If you find yourself in a whirlpool, avoid moving in the same direction as the water flow and try to stay away from the center. Try to keep the boat or kayak from filling with water. You may also find that, according to sources like the Smithsonian Magazine, the whirlpool has the potential to toss you back out.

That also being said, it has been shown that short-lived whirlpools brought on by significant major engineering catastrophes, like the Lake Peigneur accident, are capable of engulfing even medium-sized vessels like barges and tugboats.

During this event, a Texaco-hired oil rig was carrying out exploratory drilling in the lake on November 20, 1980, above the long-running salt mine owned by the Diamond Crystal Salt Company. The drilling had accidentally penetrated a main shaft of the mine. Lake water rushed into the mine, resulting in a deep hole forming in the lake and the conversion of the shallow lake's freshwater to brackish water.

However, the ensuing maelstrom destroyed or swept away the evidence that may have been utilized to pinpoint the precise cause. What is known is that the rig's 14-inch (36 cm) drill bit had been stuck for two and a half hours when the draining was first noticed. After that, the lake began to leak into the hole, enlarging it as the rushing water swept Earth and salt into the mine, filling the massive caverns left by the removal of salt in 1919.

Fifty miners raced to escape the rising waters, using mine carts and a very slow elevator to exit the mine eight at a time, but they all survived.

Up top, the oil workers saw their 150-foot derrick sucked into a lake with an average depth of three feet. The lake water then began to circle around its new "drain," turning the lake into a giant whirlpool of mud, trees, and barges. A tugboat, a dock, another drilling platform, eleven supply barges, numerous trees, a parking lot, and around 65 acres (26 hectares) of nearby Jefferson Island were all swallowed up by the resulting sinkhole.

This event created the largest waterfall in Louisiana ever created, albeit momentarily, by the Delcambre Canal's normally outflowing backward flow.

Whirlpools 101: how they form, are they dangerous, and how to survive one
The oil sheen-coated sinkhole today.

The amount of water drained into the caverns was so great that it caused the Delcambre Canal's normal flow of salt water from the Gulf of Mexico into the now-dry lakebed to be reversed.

As the lake was refilled with saline water from the Delcambre Canal and Vermilion Bay, this overflow produced for a few days the largest waterfall ever in the state of Louisiana, at 164 ft (50 m). Water entering the mine caverns displaces air, which eventually erupts from the mineshafts as 400-foot (120 m) geysers.

Despite the fact that no human lives were lost, three dog deaths were reported. The drilling companies eventually agreed to pay $45 million to the mine owners and other flooded local businesses. It was ultimately discovered that the Texaco platform had been drilling in the wrong place due to a mapping mistake.

How do you escape from a whirlpool?

For the vast majority of people, whirlpools are completely safe, as you are highly unlikely to stumble upon one unknowingly. But for people fond of watersports, especially when still a novice, they can be something of an issue.

Avoiding being sucked into a whirlpool in the first place is the best way to survive. Pull your kayak over to the side and walk downstream to check for any standing whirlpools or potentially hazardous hydraulics when kayaking in a new area.

If a whirlpool forms suddenly in front of you in the water, make powerful strokes to go to the side of the whirlpool that is moving downstream. Use your momentum and extra paddle strokes to escape the whirlpool's downstream side.

The easiest whirlpools to avoid are standing ones, but they can also be the most difficult to exit. The Old Sow is located off the coast of Deer Island in New Brunswick, Canada, and is the largest standing whirlpool in the Western Hemisphere and has been responsible for a long list of fatalities.

Up to 250 feet in diameter, Old Sow's vortex is surrounded by churning water, pits, and troughs. Your best chance of surviving Old Sow or other standing whirlpools is to try and prevent your boat from swamping and let the vortex spit you back out.

By navigating in the direction of the water flow, make your way to the whirlpool's edge. You can plunge into the water's flow beyond its reach once you are on the outside edge.

Vertical whirlpools -- also known as hydraulics -- begin with waves that roll back onto themselves. These whirlpools might be permanent or fleeting, much like other kinds.

White water is produced on the surface as the water thunderously rebounds off of itself. Dive down beneath the frothy water swirling in the backwash to avoid getting sucked into the vortex. Force yourself into the calm water that flows beneath it and keeps traveling downstream.

If you're wearing a flotation device, you might need to use your arms to drag yourself underwater.

In any case, when kayaking or boating, put on a life vest to stay afloat in case you get sucked into a whirlpool. If you are in a boat or kayak, try to stay aboard, as flotation will keep you from becoming pinned below the surface by the force of the water.

You will value the float once you are free of the hold of the whirlpool or other hydraulics and once you have recovered from the grueling sensation of getting out of it. Additionally, your personal floatation device (PFD) or kayak makes it simpler for rescuers to locate ,and assist you.

What are some interesting facts about whirlpools?

So far we've covered a lot of ground, well water, about these incredible natural phenomena. But, if you want to know more about them, here are some extra titbits of information for your delectation.

1. Whirpools and maelstroms may play an important role in the climate

Whirlpools 101: how they form, are they dangerous, and how to survive one
This image shows a spinning formation of ice, clouds and low-lying fog off the eastern coast of Greenland.

According to recent research reports, whirlpools and maelstroms in the ocean appear to impact the climate on land. As is well known, the temperature on land is significantly influenced by the dissipation and movement of heat by water currents.

Similar to this, enormous whirlpools and maelstroms that carry tonnes of water and convey heat across oceans may be responsible for some alterations in weather patterns in various regions of the planet where they are present.

Called mesoscale eddies, these circular bodies of churning water range in size from 62 miles (100 km) to 311 miles (500 km). They develop when islands or other impediments cause water patches to become unstable.

Whirlpools 101: how they form, are they dangerous, and how to survive one
Coast line shot in south Iceland.

The eddies transport enormous amounts of water and heat across the oceans before slowly ceasing to spin over the course of days or months and reintegrating with the surrounding water.

It was assumed that as they moved, the heat they carried slowly dissipated in all directions, which would have little impact on the environment. However, after measuring the amount of water and heat they carry for the first time, it has been discovered that the eddies may have a significant impact.

Scientists have also discovered that the eddies transport as much water as the strongest ocean currents. The Earth's rotation causes them to migrate largely westward. The upshot is that nearly 30 million tonnes of water arrive every second on the east coasts of continents.

2. Whirlpools and maelstroms likely have no bottom

Whirlpools 101: how they form, are they dangerous, and how to survive one
Artist's impression of a maelstrom.

In reality, whirlpools are not bottomless pits. Whirlpools frequently draw objects to the sea floor, according to experiments.

Ocean currents may then carry them along the sea floor. If the object is buoyant, it might float a great distance from the vortex before returning to the top.

3. In fact, larger ones work similarly to black holes

Whirlpools 101: how they form, are they dangerous, and how to survive one
A whirlpool near Saint-Malo in Brittany, France.

Researchers from the University of Miami and ETH Zurich claim that some of the ocean's biggest water eddies are mathematically equivalent to the enigmatic black holes of space.

Except, of course, with water not light.

Nothing caught up in these enormous ocean whirlpools can escape because the water pathways surrounding them are so closely spaced. According to reports, their abundance in the Southern Ocean is growing, causing more warm, salty water to be transported north.

But because the precise borders of these spinning water masses have remained a mystery, they have not been able to estimate this influence until recently.

Francisco Beron-Vera, research professor of oceanography at the University of Miami, and George Haller, professor of nonlinear dynamics at ETH Zurich, think they have found the answer to this conundrum.

They separated water-transporting eddies from a series of satellite images using mathematical models.

They accomplished this by observing their whirling edges, which the scientists discovered to be signs of the presence of a whirlpool inside.

Whirlpools 101: how they form, are they dangerous, and how to survive one
Artist's impression of a black hole.

According to experts from ETH Zurich and the University of Miami, some of the greatest ocean eddies in the globe are mathematically similar to the enigmatic black holes of space.

They were shocked to discover that these eddies were mathematically similar to black holes. A light beam can no longer spiral into a black hole at a certain distance.

Instead, it makes a sharp bend and returns to its starting point, making a circle. In Einstein's theory of relativity, the barrier surface created by closed light orbits is referred to as a "photon sphere."

Similarly, researchers found closed barriers surrounding a few particular ocean eddies. Fluid particles in these barriers move in complete loops, resembling the passage of light in a photon sphere.

However, because these types of ocean eddies are stable, they can also serve as a vehicle for micro-organisms such as plankton, foreign bodies like plastic waste or oil, and water with a heat and salt content that differs from the surrounding water.

4. Some companies are using whirlpools to make electricity

Far from being something to fear, it turns out that whirlpools can be harvested to make power. While not technically naturally-occurring whirlpools, the basic idea is to engineer waterways in such a way as to form a controllable whirlpool and use it to turn a water turbine.

One prime example comes from a company called Turbulent.

Its cutting-edge turbine can be put in most rivers and canals to generate energy continuously for dozens of dwellings. As the generator just requires moving water to produce energy, it also provides cheap power.

Up to 60 dwellings can be effectively powered by it. Because a self-cleaning screen captures big particles, the device has a long operational life and requires little maintenance. The best part is that it can be operated remotely.

Turbulent says its whirlpools are a much better option for areas that have rivers than solar energy. "While solar is a great way to supplement power needs with renewable energy, a small hydro plant is the clear choice wherever there is a viable river. It is cost-effective, reliable, and much more compact," explains Turbulent.

5. Whirlpools are affected by the Coriolis effect, unlike plugholes

Large whirlpools in the Northern Hemisphere spin counterclockwise, but whirlpools in the Southern Hemisphere tend to rotate clockwise due to the Coriolis effect.

The earliest description of this force was made by the French engineer Gaspard Gustav de Coriolis (1792–1843) in his article "Sur les equations du mouvements relative des systems des corps" (1835). The rotation of the Earth is what generates the Coriolis force. In the Northern Hemisphere, it causes air to be drawn to the right (counterclockwise), while in the Southern Hemisphere, to the left (clockwise).

Likewise, large bodies of water, like oceans, are also influenced by this phenomenon, and this can, in turn, affect whirlpools.

An excellent visual example is a hurricane. In the northern hemisphere, the direction of hurricane air flow (winds) is counterclockwise, and in the southern hemisphere, it is clockwise. The Earth's rotation is to blame for this by causing a rightward (clockwise) deflection that creates a cyclonic (counterclockwise) circulation around the storm's low pressure, and the Coriolis force aids in starting the circulation of a hurricane.

Whirlpools 101: how they form, are they dangerous, and how to survive one
Low pressure system spinning counterclockwise over Iceland.

What takes place around the equator? Hurricanes do not form within 5 degrees latitude of the equator. The Coriolis force is likely too weak there for air to rotate around a low-pressure region rather than flow from high to low pressure. Because the air won't rotate, it won't form a storm.

Actually, storms are dragged away from the equator by the Coriolis force.

And that is your lot for today.

While whirlpools and maelstroms have captured the imaginations of sailors and fiction writers for many centuries, the reality about them is far less terrifying. In fact, larger ones are perfectly natural and apparently crucial elements in the Earth's system.

That being said, it won't do you any harm to avoid them if you possibly can.

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