00:00A four-story water wall, which only rises once every 1,300 years,
00:04has been recorded off the west coast of Canada.
00:07Some attribute to this type of wave the disappearances in the Bermuda Triangle.
00:12Accelerated waves can be powerful enough to make containers and oil platforms sink.
00:18This Canadian aquatic monster has not hurt anyone, but it has made a sensation.
00:22And it seems that we are about to see even higher and more powerful accelerated waves in the future.
00:29The Marine Labs team, the company that owns the buoy that was caught in the Bermuda Triangle wave,
00:34had a hard time believing the data collected.
00:36A huge force emerged from nowhere, pulled the buoy down,
00:40then brought it back to the top, before taking it even further.
00:44Thinking it was an accelerated wave,
00:46they sent the data to a scientist at the University of Victoria, a specialist in the field.
00:52He analyzed them and confirmed that it was not a technical error.
00:56The wave has officially become the most extreme accelerated wave ever recorded.
01:02It was three times higher than all the waves around it.
01:05For centuries, sailors reported seeing giant waves emerge from nowhere,
01:10but no one really believed them.
01:12In 1826, a French marine scientist and officer crossed the Indian Ocean aboard his ship, the Astrolabe.
01:20During a terrible storm, he saw several waves more than 30 meters high,
01:24almost the height of a ten-story building.
01:28The crew of the ship lost one of its members,
01:30but the remaining four people, including the captain, were able to regain the firm ground to tell their experience.
01:37At the time, scientists were hardly convinced that the waves could not go beyond 9 meters high.
01:42Everyone considered that their story was not standing up.
01:45And yet, more than a century later, the cargo ship MS Munchen mysteriously disappeared.
01:51People thought it was insubstantial, just like the Titanic.
01:55And so it was a real shock to learn that there was only one lifeboat left.
02:00When the experts analyzed the damage, they concluded that it must have been hit by a wave about 20 meters high.
02:06Witnesses have told many other stories of giant waves emerging from nowhere,
02:11but scientists have officially recognized the first accelerated wave only in 1995.
02:16It entered history under the name of the Draupner wave, or New Year's wave.
02:21This northern sea monster, 25.6 meters high, hit the Norwegian gas platform Draupner on New Year's Day.
02:30It was twice as big as the waves around it.
02:33The platform had been built to resist waves 19 meters high and had the most advanced sensors of the time.
02:41But the wave did not look like anything we had studied before.
02:45So they had to admit that accelerated waves did exist, and they gave them an official definition.
02:52It is a wave more than twice as high as the one around it.
02:55It can arise at the speed of light in an agitated sea, or appear without warning in calm waters.
03:02These waves have abrupt flanks and a deep hollow below,
03:07and they look like a wall of water emerging from the surface of the sea.
03:11They are so powerful that they can swallow lifeboats.
03:16In 2007, the National Oceanic and Atmospheric Administration
03:20submitted a list of 50 historical maritime tragedies that were most likely caused by accelerated waves.
03:27Some of the events on the list did not occur in the middle of the sea, but in lakes.
03:32The Upper Lake presents a phenomenon known as the Three Sisters.
03:36It is a series of three large waves, one after the other.
03:39The second wave covers the ships' decks before the first one disappears.
03:44The third wave sinks into the gap and adds more water.
03:48These Three Sisters completely overload the boats.
03:51According to a theory, this phenomenon caused the shipwreck of the Edmund Fitzgerald cargo ship in 1975.
03:58Two main theories aim to explain the phenomenon of accelerated waves.
04:03The first is the theory of linear addition.
04:06Imagine waves moving in the ocean at their own speed.
04:10When these waves cross, they come together and become stronger,
04:14which gives birth to an accelerated wave.
04:17Then there is the theory of non-linear focalization.
04:20According to this theory, some waves form groups,
04:24and in this way, they exchange energy.
04:27Sometimes, this exchange of energy gives rise to an accelerated wave.
04:31To predict the formation of these strange waves,
04:34scientists would need an innovative radar system
04:37capable of constantly monitoring the waves near the boats.
04:42They would collect all the data and integrate it into a mathematical model
04:46that would create a real-time image of the ocean surface.
04:50The model would perform new calculations every five minutes.
04:54Thus, the crew could know if extreme waves are preparing to attack them.
04:58Such a system does not exist yet,
05:01but considerable progress has been made in this direction.
05:04Scientists from the University of Melbourne went on an expedition to Antarctica
05:09and discovered that violent winds played an important role in the formation of accelerated waves.
05:14Apparently, they would result from a mixture of violent winds
05:18and the random movement of the waves that interact with each other.
05:22This idea was first tested in a laboratory,
05:25before being confirmed in real situations,
05:27that is, in the oceans.
05:29To study these waves, scientists used 3D cameras.
05:33These cameras work like human eyes,
05:36taking many consecutive images
05:38and thus creating a 3D image of the ocean surface.
05:42The study has shown that accelerated waves
05:45occur more often when the waves are young,
05:48in other words, when they are just starting to form
05:51and are more influenced by the wind.
05:53When strong winds blow on the rising swell,
05:56they reinforce it, raise it, and make it accelerate in an inhomogeneous way.
06:01And some waves come to steal the energy of the neighboring waves,
06:04and they then grow considerably,
06:07turning into accelerated waves.
06:09Scientists noticed that these giant waves
06:11occurred about once every six hours.
06:14They did not record any accelerated waves in quieter seas,
06:18where the wind does not have as much influence.
06:20Scientists fear that accelerated waves
06:23will no longer occur more often in the future,
06:25because the atmosphere and the oceans still contain more energy.
06:29And it seems that these waves can become
06:31much more powerful than we had imagined.
06:34These researchers managed to recreate the famous
06:37Dropner wave in a laboratory for the first time in 2018.
06:41This allowed them to study these mysterious waves closely
06:44and to show that their secret lies in the way they form.
06:48We like to contemplate the quiet waves of the seaside,
06:51but the studied phenomenon occurs offshore,
06:54when waves from different directions meet.
06:57When this happens, the water is pushed upwards,
07:00which creates what is called a partially stationary or transversal wave.
07:04This phenomenon can occur at the junction of two seas,
07:07or when the direction of the wind suddenly changes,
07:10like during a hurricane.
07:11The study has shown that the greater the angle between the waves,
07:14the higher the transversal wave.
07:16Normally, when a wave breaks, it forms a white and spiky peak,
07:20and then it stops growing.
07:22But if a wave is formed with water from several directions,
07:25it can continue to grow even after breaking.
07:28These particular waves can reach a height
07:31twice as high when breaking.
07:34They are then already much more imposing than the so-called normal waves.
07:37And if we add all the power of the waves that meet like this,
07:42we get an object four times higher than what we are used to.
07:45This discovery could change the way we build our wind turbines
07:50and our oil platforms in the ocean,
07:52in order to make them safer.
07:54At present, many companies concerned
07:57do not fully account for these huge multidirectional waves.
08:01There seems to be a lot of similarity between these two phenomena,
08:05but tsunamis are different.
08:07They occur during earthquakes, volcanic eruptions,
08:10or landslides.
08:12These phenomena disturb the entire water column.
08:15At sea, you may not even notice that a tsunami
08:19is occurring.
08:20But near the shore,
08:22when they come into contact with shallow waters,
08:25these waves can reach unthinkable heights.
08:28Accelerated waves form on the surface.
08:32However, they can sometimes form in the depths.
08:36And we are talking about internal accelerated waves.
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