Hurricane Elena's erratic path over the Gulf of Mexico forced the evacuation of nearly one million people from low-lying coastal areas from Tampa, Florida to New Orleans, Louisiana. At the time, it was the largest peacetime evacuation in U.S. history. After hovering off the West Florida coast for six days, Elena finally made landfall near Biloxi, Mississippi on September 2 as a category 3 hurricane. Estimates of the total economic loss from Elena were near $1.3 billion.
Three days after Elena made landfall a higher turbidity signal can be seen in the area off Cape St. George, Florida (partially obscured by clouds) as well as in a band of turbid water in Waccasassa Bay, Florida. The turbidity in the vicinity of the Mississippi Delta is not especially high after Elena but no comparison is possible due to clouds in the before image. Sunglint is apparent in the left of the after image.
The after image depicts a dramatic cool "filament" just off the coast in the center of the image. With its "hammerhead" or "mushroom" feature it is not unlike the cool filaments and jets that are commonly observed in coastal upwelling areas such as off the west coast of North America in the spring and summer. The implied counter-clockwise circulation is opposite to the normal clockwise circulation of the Loop Current suggesting a region of high surface shear. It is an unusual feature to find in the Gulf of Mexico and was most likely caused by an intense hurricane wind generated sea surface divergence (i.e., upwelling). This image is in contrast to other hurricane SST images that depict regional areas of cooling that are more likely due to upper ocean heat loss rather than upwelling.