Hurricane Ivan prompts rogue wave rethink

Hurricane Ivan generated a wave almost 100ft high last September, as the storm passed over the Gulf of Mexico. Scientists reckon it is the tallest wave ever measured in US waters, and that it would have had enough power to literally break a ship in two.

The wave was so large that it is likely to prompt scientists to rethink their models of wave formation. Current theories do not allow for such monsters to be created, the BBC reports.

The wave never reached land, fortunately, but was recorded by the Naval Research Laboratory's ocean-floor-based pressure sensors. The wave measured a whopping 91 feet, or 27.7 metres from its peak to its trough as it passed over the instruments, and would have been around 600 feet long. However, researchers think the instruments could have missed even bigger waves during the storm.

Large waves - known as rogue waves - are occasionally reported, and have been spotted by European Space Agency satellites. However, the mechanism by which they form is poorly understood, and they were dismissed for a long time as exaggerations or fibs told by sailors.

ESA reports several such encounters: On 1 January 1995 the Draupner oil rig in the North Sea was hit by a wave whose height was measured by an onboard laser device at 26 metres, with the highest waves around it reaching 12 metres. Then, in early 2001, two cruising vessels - the Bremen and the Caledonian Star - had their bridge windows smashed by 30-metre rogue waves in the South Atlantic.

But these waves may not be rogue waves at all: lead author David Wang told the BBC: "Our results suggest that waves in excess of 90 ft are not rogue waves but actually are fairly common during hurricanes."

The research is published in the journal Science. ®

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