Rogue Wave - Background

Background

Once lacking hard evidence for their existence, rogue waves are now known to be a natural ocean phenomenon. Eyewitness accounts from mariners and damages inflicted on ships have long suggested they occurred; however, their scientific measurement was only positively confirmed following measurements of the "Draupner wave", a rogue wave at the Draupner platform, in the North Sea on January 1, 1995. During that event, minor damage was inflicted on the platform, confirming that the reading was valid. Satellite images have also confirmed their existence.

Freak waves have been cited in the media as a likely cause of the sudden, inexplicable disappearance of many ocean-going vessels. One of the very few cases in which evidence exists that may indicate a freak wave incident is the 1978 loss of the freighter MS München. In February 2000, a British oceanographic research vessel sailing in the Rockall Trough west of Scotland encountered the largest waves ever recorded by scientific instruments in the open ocean, with a SWH of 18.5 metres (61 ft) and individual waves up to 29.1 metres (95 ft). "In 2004 scientists using three weeks of radar images from European Space Agency satellites found ten rogue waves, each 25 metres (82 ft) or higher."

A rogue wave is distinct from a tsunami. Tsunamis are caused by mass displacement, such as sudden movement of the ocean floor. They propagate at high speed over a wide area and are more or less unnoticeable in deep water, only becoming dangerous as they approach the shoreline and the ocean floor becomes shallower. They do not present a threat to shipping at sea (the only ships lost in the 2004 Asian tsunami were in port). A rogue wave, on the other hand, is a highly localized phenomenon both in space and duration, most frequently occurring far out at sea.

Rogue waves may sometimes be referred to as "hundred-year waves," due to the supposed likelihood of their occurrence. They should not be confused, however, with the hundred-year wave, which is a statistical prediction of the highest wave likely to occur in a hundred-year period in a particular body of water. These predictions are typically based on wave models which do not take rogue waves into account.