How Dangerous Rogue Waves Are Formed in the World’s Oceans
iStockRogue waves are believed to be responsible for sinking ships and causing property damage to offshore structures such as oil platforms.
On Nov. 4, 2000, the 56-foot-long Channel Islands National Marine Sanctuary research vessel R/V Ballena was hit by a rogue wave and capsized near Point Conception off Santa Barbara, California. The wave was estimated to be 20 feet high. The crew survived, but the Ballena was dashed by waves against the island’s rocky shore and was a total loss.
Even more famous was the loss of the SS Edmund Fitzgerald on Nov. 10, 1975, which may have been caused by a rogue wave. The lake freighter sank suddenly during a Lake Superior gale, and went down without a distress signal in Canadian waters. All 29 members of the crew perished.
These rogue waves — aka freak waves, monster waves and killer waves — are exceptionally powerful. The new study has found that they can be exacerbated when they are produced by two sets of waves crossing at a particular angle. The results were reported in a University of Edinburgh press release.
This phenomenon, which researchers say has been demonstrated in an experiment for the first time, is also believed to have played a part in producing a 39-foot wave, known as the Draupner wave, which struck a North Sea oil platform in 1995.
iStockThe Ballena crew was trapped briefly in the capsized vessel, but managed to escape and eventually swim ashore.
Experiments were carried out in an 82-foot circular tank — the FloWave Ocean Energy Research Facility — at the University of Edinburgh and showed for the first time how large waves are affected by the angle at which they intersect.
The testing tank is able to simulate ocean currents and waves of any type, which are monitored using overhead sensors.
The study, published in the Journal of Fluid Mechanics, was carried out in collaboration with the University of Oxford and supported by the UK’s Engineering and Physical Sciences Research Council.
Dr. Mark McAllister, who took part in the research while at the University of Edinburgh, said: “These experiments provide new insight into how a heightened, or set-up, wave actually forms. They revealed that this behaves like a partial standing wave, which forms underneath waves as they cross. This insight allowed us to create a simple theory to predict when such waves might occur.”
Researchers say their understanding of rogue waves can lead to better designs of offshore structures and to safer navigation by ships in the ocean.
