Hurricanes And The Oil Spill: There's Good News And Bad News
As oil continues flowing into the Gulf the first tropical storm of the season, Blas, is rolling off the Southwest Pacific coast of Mexico and another tropical disturbance is rumbling a few hundred miles south of the gulf of Tehuantepec, we're starting to see the first real signs that hurricane season is upon us, and the realization that the situation is about to get a bit more complicated.
According to the seasonal outlook issued by the National Oceanic and Atmospheric Administration climate prediction center, an "active to extremely active" hurricane season is expected for the Atlantic Basin.
Speculation aside, it's not really a matter of if but when one of these angry monsters barrels towards the Gulf and the millions of gallons of crude sloshing around in the ocean every day.
So what happens to the oil and the hurricane when the two collide -- does it help or harm the situation?
On a big scale a hurricane's helpful, but on a local scale it could be extremely damaging depending on where it drops a concentrated pile of that oil, said Donald Van Nieuwenhuise, director of petroleum geoscience programs and research associate professor at the University of Houston.
"When you break up or disperse the spill, it makes it easier for the natural bacteria that is in the water to eat the oil, to actually biodegrade it," Van Nieuwenhuise said. "Scientists know that in warmer climates not only is bacterial action faster than it would be in the Gulf of Alaska where the Exxon Valdez spill occurred, but also the temperature helps burn off the volatiles and the oxidation occurs more quickly with some of the components of crude oil."
Where the oil would go depends on a variety of factors, especially the track of the hurricane.
He's not pointing to a hurricane...yet
"A hurricane is going to disperse most of the oil, but my big concern is that when a hurricane reaches the shoreline, typically it will increase what we know as long-shore current," Van Nieuwenhuise said. "My biggest concern -- if we get a series of hurricanes that travels south of the Texas Coast and moves parallel to the coast over a great distance, those hurricanes could potentially develop very strong long-shore currents and that will have the potential to move oil down the coast quicker than anything."
Hurricane Claudette in 2003, for example, well to the south of Galveston, created a powerful long-shore current which removed a third of the newly replenished beach south of the Galveston Seawall in one day.
"That's how powerful it is. So if it can move the sand then it will move the oil that's stuck on the beach," Van Nieuwenhuise said.
Some beached oil from the current spill has already been entrained in the long-shore current along the Louisiana coast and is already moving.
You could also have significant long-shore current develop with an easterly flow and push oil further along the Florida coast. That would require a hurricane turning east off of the mouth of the Mississippi and, as it moved to the northeast towards Florida, it would produce long-shore currents moving along the coast to the East. However, hurricanes approaching the western coast of Florida normally would heighten long-shore current to the North which would actually dampen or stop migration of oil to the South along the Florida Coast, Van Nieuwenhuise said.
What about the opposite question: What effect, if any, would a large oil slick have on an incoming hurricane?
Oil can reduce the amount of evaporation and wave action, Van Nieuwenhuise said, but it won't have much effect at all on a hurricane formed out in the Atlantic already coming in with a huge amount of power.
In addition, the National Oceanic and Atmospheric Administration says that except near the source, the slick is very patchy and would break into pools near the surface or mix as drops in the upper layers of the ocean.
In theory, for evaporation to be reduced, the layer would have to be thick enough to not allow for contact of the water to the air, so the oil slick is not expected to alter the intensity or the track of a fully developed hurricane, and will have little effect on the storm surge or near-shore wave heights.
NOAA said that storm surges may carry oil inland as far as the surge reaches.
"The hurricane can take oil way past the mouth of a bay and up to the head of the bay," Van Nieuwenhuise said. "It could go all the way into Mobile Bay for example, and that wouldn't be good."
The further up an estuary you get, the more delicate the ecosystem is, and this could be devastating.
Overall, big picture, a hurricane will make it better, Van Nieuwenhuise said, it'll speed up the process of biodegradation and oxidation and all the natural processes that eliminate oil -- the problem in this case is the enormous volume of oil.
"How bad it's going to be will have to be measured because we've never seen anything like this before in this part of the gulf. The studies they did on the Ixtoc well, which probably weren't enough, show that recovery was very quick, it was almost astounding. There is very little evidence for us to go by from those studies."
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