^ A 1940 Photo of a Ship Facing a Possible Rogue Wave in the Bay of Biscay
Image Courtesy of the National Oceanic and Atmospheric Administration (NOAA) at
Retrieved From https://en.wikipedia.org/wiki/File:Wea00800,1.jpg
The Illuminating Draupner Wave
Christmas, they say, is the season of hope. And that the New Year brings with it tons of exciting prospects. The first day of 1995 certainly was for the world of oceanography. And, it shook the very foundations of our beliefs on ocean waves.
Prodded by ominous winds, an angry sea was hurling menacing, 39-foot waves on Statoil’s Draupner Platform in the North Sea. The crew was not bothered, designed as the platform was for such weather. At 3 PM, onboard authorities ordered the crew indoors.
And this is why they missed the spine-tingling scene of the 84-foot Draupner Wave crashing into the platform at 3:20 PM at a galloping 45 miles per hour. History was in the making.
Checking logs later, the crew first thought it was a technical error. How could a wave be so tall? Destiny and oceanographic development had other plans. Other, independent sensors told the same 84-foot story. There could be no denying now.
Observers had long suspected the hand of rogue waves in many shipwrecks. But this was the first time an instrument had recorded one. The rogue wave had crossed over from folklore to reality. The elusive killer had finally revealed itself.
Until then, wave theorists relied completely on the Gaussian Theory that placed the frequency of such freak waves to once every 1,000 or 10,000 years. And it had relegated the rogue wave to the league of fantasies such as the Bermuda Triangle, sea dragons, and mermaid stories.
Serious discourse had regularly and summarily dismissed such colossal waves as fairy tales sailors told each other to pass time on long, lonely voyages. Or, as fables that sailors boasted loudly in pubs after their favorite drink had loosened their tongues beyond sanity.
People who encountered 100 feet rogue waves generally weren’t coming back to tell people about it is how Susan Casey aptly puts this in The Wave: In the Pursuit of Rogues, Freaks and Giants of the Ocean. For, this was the case until double-hulled steel ships arrived in the 20th century.
Way back in 1826, French Prime Minister Francois Arago had contemptuously mocked in public the famed French Scientist and naval officer Captain Jules Dumont d’Urville for reporting the sighting of 100-foot-plus giant waves.
In the current age of information where technology has opened many a door of knowledge for the curious eyes of mankind, rogue waves are no longer the stuff of legend and superstition. Courtesy, a laser-based, wave-height detector onboard the Draupner Platform.
Towering over the surface of 230-foot deep water, the Draupner Platform was armed with numerous gauges because this was the world’s first major oil platform of the jacket type – it was bolted to the ocean floor with bucket foundations instead of using conventional piles.
Designers were therefore keen to measure and record the forces on this new contraption of suction anchors and bucket foundations that, hitherto, was used only for securing smaller buoys. Their thoroughness opened a fresh chapter in oceanography.
Talking of oceanography, it defines a rogue wave as one whose height exceeds twice the significant wave height (SWH or HS). And, SWH is the average of the highest third of the waves as measured from trough (lowest point) to crest (highest point) of the wave within a 20 minute period.
In simpler terms, rough waves are those with heights exceeding twice those of the surrounding waves. They can be eight times as tall as the average waves in the vicinity though.
The challenge that rough waves present is not restrained to their height and force alone. They arrive unannounced from a direction other than of the prevailing winds and waves.
Known by various names such as monster waves, killer waves, freak waves, abnormal waves, episodic waves, and extreme waves, rogue waves can take down even large ships.
Observers have identified three broad types of freak waves:
- Walls of Water: that can travel up to 10 km in the ocean
- Single Waves: are short lived and formed during storms
- Three Sisters: group of three serial waves common in the Great Lakes of America
Present day ships can comfortably withstand waves that produce breaking force of 15 tons per square meter (t/m2). Large, 12 meter waves produce a force around 6 t/m2. Not an issue. The problem is, rogue waves can generate a breaking force of 100 t/m2. Brave that if you can!
Formation of such waves is a complex mechanism. It is believed they are formed by the constructive interference between fast moving and slow moving small waves. Simply speaking, the heights and depths of the slow and fast moving waves add up to create a large wave.
Constructive Interference is the combination of multiple waves to create a wave larger than the individual waves. This is possible when the waves are exactly or approximately in phase. The crest of one wave coincides with the crest of other waves as do the troughs.
High winds and strong currents generate large waves. When the crests and troughs of multiple such waves to join forces, we get a giant wall of water, the rogue wave. We shall explore their formation in detail in the second article of this series.
Apart from their incredible striking force, their troughs that come before and after the wall of water are similarly extreme. And treacherous. Battered by the punishing force of the wave, most ships never rise above these deep troughs. Malevolent by design are rogue waves.
Some researchers explain these deep troughs or holes as the result of a large wave sucking in energy and water from other waves in the vicinity. The large wave thus grows in elevation at the cost of other, smaller waves thereby creating a deep hole around itself.
A rogue wave is different from a tsunami. Seismic events such as earthquakes beneath the ocean floor displace water above them forming a large wave that flows over to the coast as a giant wave or tsunami. Precisely why tsunamis are also called seismic sea waves.
Normal ocean waves and rogue waves are the creation of winds and tides, not seismic events. Other phenomena that create tsunamis include volcanic eruptions, landslides, meteorite impacts, underwater explosions including underwater nuclear explosions, and glacier calvings.
Speaking of destructive prowess, a tsunami assumes sinister colors only when it nears the coast, not in deep oceans. Unlike rough waves that are lethal in their immediate vicinity irrespective of the location of the vicinity.
In deep oceans, tsunamis are only a foot or so high. Near the coast where waters are shallower, their immense energy makes them gain height even as their tops move faster than their bottom parts. It is this sudden rise that brings tons of water crashing down on the shoreline.
An important warning sign of a tsunami is a sudden retraction of coastal water. Kind of a mammoth low tide. This is because the trough of the tsunami reaches the shore earlier and pulls the water ocean-ward. This exposes ports and sea floor. The crest comes five minutes or so later.
We shall recount in a subsequent section the Flannen Isles Mystery wherein three caretakers on a lighthouse on islands near Scotland who were swept away by a possible rogue wave in 1899. The point being, rough waves are destructive even near shorelines.
Studies & Research Efforts
Professor Laurence Draper in 1964 composed the first known scientific article on freak waves. A definitive composition at the time, it recorded the efforts of the National Institute of Oceanography in the early 1960s when the tallest recorded wave was around 67 feet high.
Numerous pieces of evidence have corroborated the existence of rogue waves since the Draupner Wave of 1995. These include measurements by oceanographic research vessels, satellite images, pressure transducers on the ocean floor, videos, and photographs.
Researchers from Statoil presented a paper in 2000 with evidence that the frequency of rogue waves is greater than the assumed once every 1,000 or 10,000 years. In November 2000, leading researchers flocked in Brest for the inaugural Rogue Waves 2000 workshop.
British oceanographic vessel RRS Discovery encountered the highest ever recorded rogue wave in open oceans in February 2000 while sailing in Scottish waters. It measured an imposing 95 feet.
Then in 2004, radar images from the satellites of the European Space Agency revealed ten rogue waves each with a lofty reach of 82 feet or higher. And, all these occurred within a span of three weeks only and within a limited geographical area.
These images were the proverbial final nail in the coffin of the old set of assumptions for they established the widespread existence and the high frequency of rogue waves. But because of their short life spans, ships rarely encounter them.
Professor Akhmediev of the Australian National University is a leading researcher on this topic. According to him, there are about ten rogue waves in the world’s oceans at any given moment.
Satellite images have also revealed the favorite hangouts of rogue waves – areas where ocean currents meet waves traveling in the opposite direction. The problem is, rogue waves can also appear in areas without strong waves and currents.
Numerous other universities and organizations are studying various facets of rogue waves. Some, noteworthy efforts include:
- Project MaxWave: is a European project that utilizes diverse remote sensing techniques to better understand the physical processes that create rogue waves and pinpoint the geophysical conditions where these waves are most likely to occur
- US Naval Research Laboratory: published the results of their modeling efforts in 2015
- Swinburne University of Technology, Australia: recently came out with its work on the probabilities of rogue waves
- Umea University, Sweden: demonstrated in 2006 how normal waves can suddenly grow into rogue waves
- University of Oslo: has researched the umpteen facets of rogue waves such as rogue wave probability, non-linear wind waves and their modification by tidal currents, General Analysis of Realistic Ocean Waves (GROW) and the like
Case Files: Rogue Waves of the Pre-1995 Era
But before the world acknowledged the existence of the rogue wave, there were umpteen cases that puzzled many an investigator. And although a few wise men turned the needle of suspicion towards the (then phantom-like) rogue wave, lack of definitive evidence secured its acquittal.
At 200 meters long and loaded with cutting edge gadgetry, German merchant ship MS Muchen was said to be capable of withstanding anything that the ocean dished out. Perhaps a civilian version of the famed World War II German battleship Bismarck, the unsinkable.
But while an act of man sunk the Bismarck in a naval battle in May 1941, it was the hand of nature that put down the Muchen in December 1978. Enquiry blamed an unknown weather event. But the signature of a rogue wave was there to see for those who ventured beyond the obvious.
One lifeboat of the MS Muchen, found later, had broken free from her robust holding mechanism. This, when the lifeboats were locked 20 meters above water level! Only a mammoth force could wreck such damage at such height.
From German technology to British bulk, rough waves have left their mark everywhere. Investigators sensed their presence in the sinking of the MV Derbyshire in 1980 when all her 44 crew members lost their lives. This remains the largest British vessel lost at sea, ever.
Reopening the Flannen Isles Mystery points to rogue waves again. Three keepers stationed at a lighthouse on a remote island near Scotland vanished in 1899. Damage to a metal box stored 30 meters above water and a huge rock that had moved from its place implicates rogue waves.
Some observers accused a rogue wave of sinking the semi-submersible mobile offshore drilling unit Ocean Ranger on February 15, 1982. This one was a real tragedy, for all 84 crew members met their end in a watery grave while drilling near the Grand Banks of Newfoundland.
Lakes are not immune to rogue waves. Lake Superior is known for the Three Sisters phenomenon – a series of three huge waves hit a ship quick succession, the succeeding wave slamming before its predecessor clears. The event is suspected of sinking SS Edmund Fitzgerald in 1975.
This too was a calamity as the entire crew of 29 perished. The ship was the largest ship to ply in America’s Great Lakes when she was launched in 1958. Till date, she remains the largest to have sunk there.
Lighting a lamp removes darkness only from a limited area. The problem with us humans is, we mistake the bright area for the entire universe. And we do not widen our gaze till an unstoppable force from the dark shadowy world beyond the bright-lit area hits us with gale force.
The rogue wave gave us this wakeup punch on January 1, 1995. Although we have mended our ways since then, we still have miles to go before we can rest. For, the woods around rogue waves still remain blindingly dark and puzzlingly deep.
In the second article of this series, we take a look into how exactly a rogue wave batters and sinks a ship. And we study the efforts of varied institutions for predicting rogue waves.
Wish to know more of other peculiar phenomena in oceans? Visit our blog.