Rogue Waves Are Mysterious And Big

Stand by the shore and watch the waves roll in, and you’ll notice that most come in at roughly the same size. There’s a little variation, but the overwhelming majority don’t stand out from the crowd. On all but the stormiest of days, they have an almost soothing regularity about them.

Every so often though, out on the high seas, a rogue wave comes along. These abnormally large waves can strike with surprise, and are dangerous to even the largest of ships. Research is ongoing as to what creates these waves, and how they might be identified and tracked ahead of time.

Myth Becomes Reality

The MS Riverdance was run aground after being struck by a rogue wave off the coast of Blackpool in 2008. The ship was eventually dismantled on site as attempts to refloat the vessel failed. Credit: Susan Noble, CC-BY-SA 2.0

Stories of rogue waves have long been part of maritime folklore and legend. For centuries, sailors told tales of “walls of water” that would appear out on the open seas, dashing ships to pieces as the towering waves crashed over the vessel.

They’re not to be confused with tsunamis, either. Those are generally caused by the displacement of water from a volcano or earthquake or similar large disturbance. Tsunamis barely show up as more than a ripple in the ocean, only towering once they get close to breaking on the shore. Rogue waves are quite the opposite, standing at great height in open seas and posing a major danger to any ships or platforms caught in the path.

Despite many anecdotes of such phenomena, however, mainstream science was slow to accept the existence of rogue waves. Established models for wave creation and propagation simply couldn’t account for such behaviour. Thus, rogue waves remained largely ignored by the scientific literature. A handful of papers and texts looked into the idea of freakishly large waves, but the concept was seen as little more than a curious myth.

The accurate recording of the rogue wave that hit the Draupner platform in 1995 sparked a change in the broader scientific community, leading to a flurry of research to better understand rogue waves. Credit: Paolosan, CC-BY-SA-4.0

That all changed in 1995. The Draupner gas pipeline platform in the North Sea was struck by a rogue wave with a maximum wave height of a full 25.6 meters. It was a huge wave, well above the typical significant wave height of just 12 meters in the locality during typical conditions. The big break was that the Draupner platform was fitted with an accurate laser rangefinder wave recorder, which recorded the height of the wave accurately as it passed by. Thankfully, the platform only took minor damage, but the data captured went on to shake up oceanography for years to come.

The measurement of the Draupner wave completely changed the scientific consensus; there was now unarguable proof that rogue waves really existed. Research took off in earnest, with scientists quickly realizing that rogue waves fell outside of the typical Gaussian models used to predict wave height and activity.

By the early 2000s, scientists had determined that rogue waves weren’t obscure, 1-in-10,000 year events, either. By 2004, satellites of the European Space Agency were being used to spot rogue waves out in the ocean. Researchers found ten rogue waves over 25 meters in height after surveying a section of the South Atlantic for just three weeks.

In a relatively short time, science had gone from disbelieving in rogue waves to now finding them regularly showing up all over the world. It raised serious concerns, particularly in the world of ship design. Modern merchant vessels had traditionally been designed to withstand wave heights in the realm of 11 meters. Now, there’s a better understanding that waves in excess of 20 meters are not unexpected, and waves up to 30 meters are possible. It’s led calls to increase the minimum wave height that ships are intended to withstand, to give merchant vessels a greater chance at surviving an encounter with a rogue wave.

Hunting for an Answer

The modern definition of a rogue wave is a wave that is more than twice as high as the significant wave height. The significant wave height is determined by taking the mean of the top third of waves in a given sea state. Thus, a rogue wave stands out by being over twice as high as other tall waves in a given area.

Scientists hope to better understand what causes rogue waves to form. Rather than a single cause, current research suggests that a variety of different factors can come into play to generate a rogue wave.

A simulation of the Draupner wave performed in 2019. In the first row, waves meet at an angle of 0 degrees, while meeting at 60 degrees and 120 degrees respectively in rows 2 and 3. Note the significant rise in height in the third row, where researchers found a vertical jet of water rapidly increased the wave height. Credit: McAllister et al 2019, CC-BY-4.0

Constructive interference is one of the simplest ways that a rogue wave can form. This is where separate waves travelling through the water come together and meet, wherein their peaks and troughs happen to line up, and the waves constructively interfere to become larger than before. Simulations have suggested that the angles at which these wave trains meet could play a significant role. One simulation showed that waves meeting at a 120 degree angle led to steep rogue waves being generated.

Interactions between wave swells and ocean currents are also suspected to be a way for rogue waves to form. This mechanism is thought to be at play off the coast of South Africa, where large rogue waves form in the region of the powerful Agulhas current. Where a swell travels in the opposite direction of an ocean current, the current is thought to have a focusing effect on the waves. The current slows the wave front, pushing subsequent waves closer together and raising the overall wave height.

Other explanations include non-linear phenomena, where one wave in a series of waves may suck energy from those around it, becoming larger in itself. This phenomena has been demonstrated in the lab successfully in water tank tests.

Research is ongoing into better predicting and understanding these wave events. A recent research paper has been published on trying to observe rogue waves in the field aiming to explore these causative effects. A wave buoy outfitted with inertial measurement systems and differential GPS for high accuracy was used to measure a rogue wave off the coast of Canada in 2020 through to 2021.

The study managed to capture data on a rogue wave of 17.6 m trough-to-crest height, in a sea state where the significant wave height was just 6.05 m by comparison. With a height ratio of 2.9 relative to the significant wave height, and a crest height 1.98 times higher, the study’s authors believe this to be the largest normalized rogue wave height thus far recorded. Notably the team did not discover evidence for non-linear effects in the generation of the rogue wave.

It’s likely it will take many years of further research and modelling before the rogue wave phenomena is truly understood. The efforts will only be hoped by better understanding, with more seafarers and researchers aware of rogue waves and thus better able to capture data on them when and where they occur.

34 thoughts on “Rogue Waves Are Mysterious And Big

    1. Changes could happen once insurance companies start including some sort of additional fee to deal with the possibility of rogue waves. Or they could make rogue waves not covered by regular maritime insurance at all unless special ‘rogue wave insurance’ is purchased.

    2. The insurers will charge more and new ships will have to be designed for bigger waves. Old ships will be retired early -i.e. sold to people/governments who will operate them without insurance- because it will cost too much to retrofit them and/or keep them insured.

      1. I’m would not assume that ships+cargo are fully insured. I guess that the shipowner might calculate their risks and only insure a fraction.

        And even if fully insured, the loss of a ship can’t be instantly compensated. So they would lose a lot of business.

        That said, I think there is a lot of ignorance. Just ignore the problem, it goes away and won’t happen to me.

        1. Based on your last sentence, I would enjoy the documentary (er, I mean comedy) “Don’t Look Up.” Sit tight and assess is the key phrase.

  1. “”Despite many anecdotes of such phenomena, however, mainstream science was slow to accept the existence of rogue waves. Established models for wave creation and propagation simply couldn’t account for such behaviour. Thus, rogue waves remained largely ignored by the scientific literature. A handful of papers and texts looked into the idea of freakishly large waves, but the concept was seen as little more than a curious myth.””

    That is strange, because on my understanding of wave theory, I would have expected them to be not very uncommon but short lived (in comparison to “normal” sized waves”) It’s a relatively simple constructive interference thing, but where the properties of water and gravity will damp them back down to “normal” after some time.

    As is the problem with relatively infrequent events, if they don’t happen where humans are frequently located, and observed, they get written off as legendary/imaginary/mythical, even though there might be phenomena that are rarer, but visible within large population centers, so very adequately witnessed. (Like maybe cities on large rivers that only have a tidal bore happen with particularly high tides or specific weather conditions, low pressure, wind up or down the river, etc. )

    1. Whatever is going on is obscured by calling everything a “wave”. I also see constructive interference in most of them. Are any of these giant waves actually seen moving anywhere? Not that they can’t, but they should not without something special going on. The assumptions made for modeling large waves in water need to be more accurate the bigger it gets. And what do the swirly bits from the previous waves do to it?

      Anyway, the graph from the oil platform is telling. It shows a sudden rising and falling of the water in a way that looks impossible for a wave. So maybe it wasn’t a wave. And maybe that is the conclusion of researchers as well. I can’t tell when everything is called a wave.

  2. “Stand by the shore and watch the waves roll in, and you’ll notice that most come in at roughly the same size. ”

    This isn’t so, or at least not generally, or at least only for very high values of “roughly”. Waves come in sets, often you’ll get 3 large waves then nothing for a while, or depending on conditions every 5th or 7th wave may be a lot larger. There are also variations on this, like 7 sets of 3 waves, where the 7th set is significantly larger than.

      1. Definitely not wake from a passing boat.

        Note, this has been observed by many different people, in many different places, for a long time. If you live in a fishing village this will be passed down word of mouth, so you don’t push out in your fishing boat right as the big set/wave will hit. If you surf (or kayak in open ocean), you will know that the waves are different sizes, and some you ignore, some you catch, and some you run from… if you paying attention you can count them and be ready before the big wave(s) appear.

      2. The clustering of a few large waves followed by longer periods of smaller ones is a phenomena well-known to the surfing community. The common image of a surfer sitting up-right, straddling a board, depicts the period of waiting for the next great set. I’ve always attributed the phenomena to the constructive / subtractive interactions of two different wave frequencies getting overlaid… going in-and-out of phase.

  3. There’s a couple on rogue wave events on video in the Deadliest Catch series. One in season 2 knocked a boat on its side. The boat was being steered into the waves during a storm, but the rogue came at them broadsides.

    1. I’d be wary of taking evidence from reality TV shows. It’s trivial to edit together an unrelated rolling (e.g. a rudder fault during a storm) and some footage of water washing over the deck, to make a fairly uninteresting incident into an exiting one. Cut quickly enough and it doesn’t even need to be the same day or same vessel to be believable.

  4. Are these categorized differently from microburst and shelf landslide rogue waves? Because the 1995 acceptance thing seems a little late given the massive amount of evidence gathered for prior events and the rapid response by the scientific community to pinpoint events that led to disasters.

    A wave 18 ft high, 250 ft long and 27 miles wide hit Daytona Beach on Friday, July 3, 1992, at 11 PM on a holiday weekend in a location where people were allowed to park on the beach, so it was a little expensive. Sand slipping down the shelf got credit for making a few memorable vacation memories.

    1. I think these are rogue waves specifically because no obvious cause had been identified. Subsurface activity like shelf landslides or earthquakes are identifiable causes.

  5. The’re big, but not mysterious. Maybe they were mysterious 30 years ago but it’s a real and serious issue because enormous amounts of valuable cargo are transported over the seas, oil drilling rigs, and lately also windmill farms and other stuff.

    Just start by “wave research laboratory” in some search engine, or if you’re more looking for some visual entertainment then:

  6. Sometimes it pays to listen to stupid uneducated people like fishermen, and not use our new, modern, settled science that everyone who’s not an idiot knows, to drown out what others have known for generations.

    1. Professional navies have been around for 2500 years with a primary charge of protecting maritime commerce, which includes listening to those kinds of reports and investigating them.

      Fishermen also reported mermaids and the one that got away that was “this big.”

  7. I sort of understand why scientists are remiss to investigate something for which there is scant empirical evidence. I also understand being cautious about accepting the word of superstitious 18th century sailors on matters of the High Seas.

    But seriously? 1995? Sailors talked about these things for centuries, and then CONTINUED to talk about them all through the 20th century, long after they’d given up their stories of sea dragons and the kraken.

    But no, “we haven’t got some numbers and squiggly lines on a chart, and our models say they don’t exist, so we aren’t even going to attempt to investigate.”

    I’m not saying scientists should accept things that don’t have evidence by the way. I’m saying they should perhaps research things that many people keep talking about, if there has been basically no research done yet, instead of assuming the model works properly.

    Eg, they don’t need to look into flat earth nonsense because MANY scientists have looked into that, enough to show the laymen are wrong, so the chattering of those laymen is irrelevant.

    But they absolutely should look into things for which no real investigation has taken place, especially if the layman’s chatterings have continued, beyond 1900, in a professional field like shipping.

    1995, for Woden’s sake.

    1. There were plenty of wave height measurement devices in operation for decades (the one installed on Draupner was not an abnormality) that failed to record any evidence of rogue waves. Whilst absence of evidence is not evidence of absence, it is generally a dead giveaway.
      Whilst “those durned scientists never believed us when we told them for years!” makes for an attractive story, there are plenty of reported phenomena that continue to have zero evidence towards them, that have also been investigated for decades with zero evidence for them. The occasional Coelacanth does not provide credibility to the hundreds of lake monsters reported.

  8. It’s vogue to ignore science. Why bother trying to predict rare astronomical events like Coronal Mass Ejections, supernovae, and the like? What about earth quakes, volcanoes, hurricanes, tornados, or even lightning? Just a bunch of silly stuff, right? Shouldn’t we work harder on the meaningful stuff like politics?

    Here’s are thought: maybe they didn’t “see” the rogue waves because they had no detectors designed for the extreme magnitudes of those events? How many bits of ADC range is needed? That how the science of seismology evolved (TI was a pioneer in that field, but for oil exploration). There was a reference to Gaussian (distribution) in the article, but no mention of many sigma from the mean are these events? Wasn’t the big bang essentially a rogue wave?

  9. I was guest aboard a friend’s small sailboat one midday. We were sailing eastward & suddenly realized that a wave of perhaps 15′ height was almost upon us. Our bow knifed thru the wavefront & the boat instantly stopped. We had been sailing into waves approx one foot trough to crest when this monster appeared.

Leave a Reply

Please be kind and respectful to help make the comments section excellent. (Comment Policy)

This site uses Akismet to reduce spam. Learn how your comment data is processed.