An eddy that broke off from the powerful, but unpredictable, Loop Current induced an explosion of strength in Hurricane Katrina, but in the summer of 2010, the current failed to carry the expected tar to the Florida Keys and beyond. Briefly, the ocean current transports warm water from the Caribbean between Cuba and Mexico's Yucatan peninsula into the Gulf of Mexico. It initially flows northward in the Gulf, then follows an omega-shaped path moving southeastward till it becomes the Florida Current just south of the Florida Keys. From the tip of Florida, it goes northward again, up the U.S. coast. At this point, it has become the Gulf Stream.
The Loop Current is present in the Gulf about 95 percent of the time. A fast-moving current, its width varies from 125 to 190 miles, and the warm waters reach to approximately 2,600 feet below the surface. The current is driven along by winds, thus the difficulty in predicting its movement.
Loop Current Rings or Eddies
Although the Loop Current stays in the eastern region of the Gulf of Mexico, never traveling west of the waters below Mississippi, it has had a tremendous effect on hurricanes that struck Texas and Louisiana. This happens because every six to 11 months, a "warm core ring," or clockwise-circulating eddy, breaks off from a bulge in the main current and drifts westward or southwestward. These offshoots of 85-degree waters are capable of fueling rapid intensification of tropical storms or hurricanes that leave the cool surrounding waters and cross their paths.
As an example, in 2005 the Loop Current shed an eddy in July that remained adrift in August, when Hurricane Katrina encountered it and bloomed to Category 5 strength. The eddy was still in the Gulf drifting westward three weeks later, when Hurricane Rita passed over it, also making history as one of only 28 Atlantic Basin hurricanes to reach Category 5 intensity since 1930. Both Katrina and Rita entered the Gulf as relatively mild tropical depressions.
British Petroleum Oil Spill
About a month after British Petroleum's damaged offshore oil-drilling well began leaking in April 2010, Florida's Sun-Sentinel newspaper warned that the oil slick would likely travel all the way along the Loop Current/Gulf Stream. Waters were expected to be polluted from the Keys to Miami and on up the Atlantic coastline. At that time, the contamination problem would have extended far beyond the Louisiana wetlands.
In July, two months after the Sun-Sentinel article appeared, another Florida newspaper, the St. Petersburg Times, told a much different story. The Loop Current suddenly changed course. No BP oil had reached the Keys or the east coast of Florida, and none was anticipated in the immediate future. Scientists remain watchful, however, as the Loop Current will eventually reorganize itself.
Attempts at Predictions
The biggest question this summer: What will happen if a forming hurricane hits the warm Loop Current or one of its eddies where oil debris remains in the water? The U.S. Naval Research Laboratory offers a month-ahead forecast of the movement of the Loop Current, but currents are driven by wind, and wind pattern predictions are only reliable about 10 days out. As Frank Muller-Karger, a biological oceanographer at the University of South Florida told the St. Petersburg Times, "It's not only hard to predict, it's almost an art to forecast."
Sources
Gibson, William. “Loop Current poses oil-spill threat to Atlantic.” sun-sentinel.com. Accessed July 23 2010.
Hayes, Stephanie and Sanders, Katie. “As loop current splits, South Florida catches a break.” tampabay.com/news. Accessed July 23 2010.
“Loop Current Powers Hurricanes.” loe.org. Accessed July 23 2010.
Masters, Jeffrey. “The Gulf of Mexico Loop Current: A Primer.” wunderground.com. Accessed July 23 2010.
Mary Simpson - Mary Simpson holds a BA in journalism and an MA in English from the University of North Texas. After living in all of the major cities of ...
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