Hurricane Ivan last year whipped up waves 90 feet high, which could snap a ship in two or dwarf a 10-floor building, scientists have revealed.
The ocean waves generated by Ivan, which left a trail of devastation through the Caribbean, are thought to be the tallest and most intense yet measured.
Scientists calculated their heights using information from sensors housed in saucer-shaped moorings on the sea floor, according BBC reports.
The sensors, at depths of 60 and 90 metres, measured the increase in water pressure as the hurricane swept overhead.
The giant waves were recorded about 75 miles south of Gulfport, Mississippi, and 50 miles east of the coast of Louisiana, US.
They disintegrated into the stormy Gulf of Mexico before reaching land.
The researchers, led by Dr William Teague of the Stennis Space Centre, Mississippi, believe they missed the largest waves, estimated to exceed 132ft in height.
They wrote in the journal Science: “Measurements of the extremely large waves directly under Ivan may act as a starting point for improving our understanding of the waves generated by the most powerful hurricanes.”
Most previous attempts to measure the biggest ocean waves have failed.
“Our results suggest that waves in excess of 90 feet are not rogue waves but actually are fairly common during hurricanes,” Teague said in an interview.
Wave-measuring instruments attached to oil-drilling platforms often snap off before the peak of the storm.
In September 2004, Hurricane Ivan ripped through Grenada before passing over Jamaica, Grand Cayman, and other islands leaving death and destruction in its wake.
It ploughed through the Gulf of Mexico and smashed into the US coast on September 15.