Record wave during Hurricane IvanTheallIneed.com/NC&T/NRL
The possibility of a super wave is often suggested by anecdotal evidence such as damage caused by Hurricane Ivan in September of 2004 to an offshore rig in the Gulf of Mexico that was nearly 80 feet above the ocean surface. Hence, some of the destruction done by Ivan has been attributed to a rogue wave. According to industry and national weather sources, the damage done by waves during Ivan has been on the extreme high end for a category 4 hurricane. Ivan has been the most expensive hurricane ever for the oil and gas industry in the Gulf. The Minerals Management Service (MMS) reported that Ivan amazingly forced evacuation of 75% of the manned platforms in the Gulf (574 platforms) and 59% of the drilling rigs (69 rigs), set adrift 5 rigs and sunk 7 rigs entirely. However, the damage by Hurricane Ivan in the oil fields in the Gulf cannot be measured by how many platforms or rigs were destroyed. The most costly damage is believed to have been made to the underwater pipelines. Aside from obvious leaks, some pipelines were reported to have moved 3000 ft while others were buried under 30 feet of mud and cannot be found. The most extensive damage to the pipelines is attributed to undersea mudslides (equivalent to a snow avalanche) and to extreme waves. The complete findings of this study are published in the August 5, 2005 issue of Science.
During NRL's Slope to Shelf Energetics and Exchange Dynamics (SEED) field experiment, six current profiler moorings that also contained wave/tide gauges (Sea-Bird Electronics SBE 26) were deployed on the continental shelf at water depths ranging between 60 and 90 meters just west of the DeSoto Canyon, about 100 miles south of Mobile Bay, Alabama. An additional eight deep moorings were deployed down the shelf slope but did not contain wave/tide gauges. Fortuitously, between 8:00 pm CDST and midnight on September 15, the eye of Ivan passed through the center of the array, and almost directly over moorings 2, 5, 8, and 11. Historically, instruments in the ocean do not even survive near misses of such powerful storms, much less direct hits. Fortunately, all of the SEED moorings survived this powerful storm, and provided the best ocean measurements of currents and waves ever obtained directly under a major hurricane.
|The eye of Hurricane Ivan is clearly shown just southeast of the boot of Louisiana. NRL SEED moorings (blue dots 1-14) were deployed on the Mississippi/Alabama shelf and slope in May 2004, and were serviced in November. All of the moorings contained acoustic Doppler current profilers while moorings 1-6 additionally contained wave/tide gauges. Final recovery of the moorings is scheduled for May 2005. The path of Hurricane Ivan through the moorings on September 15 is indicated by the green dots (Photo: NRL)|
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