4-Story rogue wave spotted in the Pacific Ocean in 2020 is most extreme ever reported

02/21/2022 / By Kevin Hughes

A four-story rogue wave that turned up in the Pacific Ocean off the coast of Canada in 2020 is the most extreme example of such phenomenon ever reported, according to scientists who described it as a “once in a millennium” incident.

Rogue waves, also called freak or killer waves, are large waves that occur in the open ocean apparently from nowhere.

The rogue wave was spotted on Nov. 17, 2020, around 4.3 miles off the coast of Ucluelet on Vancouver Island in British Columbia, by an oceanic buoy belonging to Canadian-based research company MarineLabs.

In a new study published online Feb. 2 in Scientific Reports, scientists said the Ucluelet wave was around 58 feet tall. It formed in a sea state of around 19.5 feet, making it just under three times as large as neighboring waves, which is the most extreme size difference ever recognized.

“Proportionally, the Ucluelet wave is likely the most extreme rogue wave ever recorded,” lead author Johannes Gemmrich, an oceanographer at the University of Victoria in British Columbia, said in a statement. “Only a few rogue waves in high sea states have been observed directly, and nothing of this magnitude. The probability of such an event occurring is once in 1,300 years.”

Rogue waves are massive “walls of water” in the open ocean

According to the National Oceanic and Atmospheric Association (NOAA), rogue waves are massive “walls of water” that form and disappear in the open ocean. They are different from tsunamis, which are caused by disturbed water from underwater earthquakes, landslides or volcanic eruptions and do not become enormous until they approach the coast.

A rogue wave is scientifically described as being at least twice as tall as the surrounding sea state — the average height of the waves for a given region at a given time.

NOAA researchers believe rogue waves are formed when smaller waves combine into larger ones, either due to high surface winds or changes in ocean currents brought by storms. Nevertheless, the precise mechanisms behind the unusual crests are still something of a mystery, according to the statement.

The first officially recognized rogue wave is called the Draupner wave, which happened in Norway in 1995, although scientists have suspected the existence of rogue waves long ago.

Stories of sailors being caught out or even killed by unusually huge waves have long filled maritime folklore, but until that 1995 report, scientists have never noticed them. Scientists have examined only a handful of rogue waves since then, but they believe that one forms every two days somewhere in the world’s oceans.

Draupner wave estimated to be 84 feet high

The Ucluelet wave is not the largest rogue wave ever recorded. The Draupner wave, for example, was estimated to be 84 feet high. However, the sea state during the Draupner wave was around 39 feet, making the rogue wave just over twice as tall as surrounding waves.

Rogue waves are normally ignored. However, if a ship or oil rig were to be caught in one of these freakishly huge crests, the result could be disastrous.

“The unpredictability of rogue waves, and the sheer power of these ‘walls of water’ can make them incredibly dangerous to marine operations and the public,” said MarineLabs CEO Scott Beatty.

But researchers hope that grids of monitoring buoys, such as the 26 MarineLabs buoys strategically positioned along North American coastlines, could disclose more about these oceanic anomalies.

“The potential of predicting rogue waves remains an open question, but our data is helping to better understand when, where and how rogue waves form, and the risks that they pose,” Beatty added.

Researchers commonly use buoys to help determine the heights of large waves.

For this study, the MarineLabs buoy recorded data in 20-minute bursts every 30 minutes. Researchers then examined the data until May 21, 2021 to verify its results.

“Most observations are at a single buoy, a single location, and so the wave passes through. And we know at this moment it was this high, but we don’t know how long. That is the big science question,” Gemmrich said.

Other important questions researchers are hoping to answer include figuring out how rogue waves are formed so that they can better predict when they will occur.

Advanced buoy technology might be a good starting point.

“We are aiming to improve safety and decision-making for marine operations and coastal communities through widespread measurement of the world’s coastlines,” Beatty said. “Capturing this once-in-a-millennium wave, right in our backyard, is a thrilling indicator of the power of coastal intelligence to transform marine safety.”