A breakthrough in documenting Rouge Waves?

The North Sea on New Years Day 1995

Shortly after 3:20pm on New Year's Day in 1995, a monster wave crashed into the Draupner oil platform in the North Sea off the coast of Norway. Hurricane force winds were blowing at the time and significant wave height was was 35.4ft (10.8m). But one particular wave that hit the platform would shape oceanography forever. The monster wave was measured to 25.6 metres.

The platform was fitted with state-of-the-art laser wave recorder on the platform’s underside enabling recording of data which lead to the conclusion that a wave never before recorded had hit the platform. 

According to existing assumptions, such a wave was possible only once every 10,000 years. 

Freak waves are no longer a myth

Stories of rouge - or freak waves have been told by mariners for centuries. With little evidence, and the size of the waves often growing with each telling, scientists long dismissed them as tall tales. But the Draupner wave changed that and set off a spur of interest among scientists and maritime companies around the world. 

Today a rouge wave is defined as a wave that is more than twice as high as significant wave hight. Significant wave height (Hs) is defined as the average height of the highest one-third waves in a wave spectrum. For many, this might seem a little abstract. But, for anyone who listens to a marine forecast, this is crucial knowledge. 

A forecast of 10-foot seas in open waters means a mariner should expect to encounter a wave spectrum with many waves between 6 and 10 feet along with a small percentage of waves up to 16 feet and possibly even as large as 20 feet. Waves that can vary from 60% up to 200% of significant wave height during passage in open waters are worth taking in to consideration when planning a passage.

A forecast of 10 foot seas are almost never only 10 foot seas.

A workshop of leading researchers from around the world attended the first Rogue Waves workshop held in Brest, France in November 2000. Since then a number of private and public bodies have funded and contributed to scientific studies on rouge waves. Proceedings from the workshop in 2008 can be found here.

RSS Discovery. Photo by: National Oceanography Centre

RSS Discovery. Photo by: National Oceanography Centre

Also in 2000 the British oceanographic vessel RRS Discovery recorded a 29-metre (95 ft) wave off the coast of Scotland near Rockall. This was a scientific research vessel and was fitted with high quality instruments. The subsequent analysis determined that under severe gale force conditions with wind speeds averaging 21 metres per second (68.9 ft/s) a ship-borne wave recorder measured individual waves up to 29.1 metres (95.5 ft) from crest to trough, and a maximum significant wave height of 18.5 metres (60.7 ft). These were some of the largest waves recorded by scientific instruments up to that time.

Occurs more often than one thought

According to ESA, The European Space Agency, severe weather has sunk more than 200 supertankers and container ships exceeding 200 metres in length during the last two decades. Rogue waves are believed to be the major cause in many such cases. 

A lifeboat passes in the wake of a cargo ship. Photo by: Daniel Novello

A lifeboat passes in the wake of a cargo ship. Photo by: Daniel Novello

In December 2000 the European Union initiated a scientific project called MaxWave to confirm the widespread occurrence of rogue waves, model how they occur and consider their implications for ship and offshore structure design criteria. And as part of MaxWave, data from ESA's ERS radar satellites were first used to carry out a global rogue wave census.

Over a short period of only three weeks the MaxWave team identified more than ten individual giant waves around the globe above 25 metres in height.

Now photographic evidence is made possible in 3D

There are three key questions that remains a mystery. Why do rouge waves form, how and how frequent they occur.

A new initiative from the University in Bergen, Norway together with NUI Galway (National University of Ireland) will try to find the answers.

In December 2017, MET Norway (The Norwegian Meteorological Institute) and NUI Galway, in collaboration with ConocoPhillips, deployed a stereo-video system on the Ekofisk complex in the central North Sea. This is the first fixed open-ocean stereo-video installation in the world.

Ekofisk is unique with its array of wave instruments, situated in a region where the 100-year return wave height exceeds 12 m. This allows researchers to observe individual waves in open-ocean storm conditions using a truly unique technique which gives a complete picture of individual waves as they come rolling in. The cameras can take up to 5 high res frames pr second and superimposing the two images allows researchers to create and measure a 3D image of each individual wave. 

The stereo-video system installed at Ekofisk in December 2017. Photo by: MET Norway

The stereo-video system installed at Ekofisk in December 2017. Photo by: MET Norway

Tales of horrendous weather, screaming winds and rouge waves have appeared in yachting literature since the days of Joshua Slocum. Evidently this, and other events, has resulted in learning more about survival strategies and has vastly improved yacht design and the quality of safety equipment. The research being done by the above mentioned and others are a significant contribution to all mariners in the future. 

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