By Sid Perkins
From New Orleans, at the Joint Assembly of the American Geophysical Union
As Hurricane Ivan approached the U.S. Gulf Coast last September, it passed right over an array of seafloor sensors. The network detected the largest wave ever measured by instruments—one that towered more than 27 meters from trough to crest.
The 50-kilometer-wide group of 14 instruments was deployed in May 2004 to measure currents on the ocean floor, says William J. Teague, an oceanographer at the Naval Research Laboratory at Bay St. Louis, Miss. Late on the evening of Sept. 15, Ivan—moving northward at a pace of about 18 kilometers per hour and packing winds of around 200 km/hr—swept across the array over a period of several hours.