Hurricanes and the Oil Spill

Ken AshfordDisasters, Energy and Conservation, Environment & Global Warming & Energy, WeatherLeave a Comment

With hurricane season upon us, questions are being asked about the effect of hurricanes on the oil spill and, conversely, the effects of the oil spill on hurricanes.  NOAA has the "answers", although it involves a lot of guesswork, since there's never been a situation where a major hurricane passed through an oil slick of this size.

I have reprinted NOAA's Q&A in its entirety below the fold.

NOAA has recently answered several questions regarding tropical development in the Gulf of Mexico and whether the oil spill will play a role in the 2010 Atlantic Hurricane Season. 

Will a hurricane passing over the oil spill have negative or perhaps maybe a positive impact? 

Where will the oil go once a hurricane moves over or near the spill?

Will the oil actually slow tropical development?

These questions and more are answered courtesy of NOAA.

What will happen when a hurricane tracks through the oil spill?

The high winds and seas will mix and disperse the oil which can help accelerate the biodegradation process.

The high winds may distribute oil over a wider area, but it is difficult to model exactly where the oil may be transported.

Storms' surges may carry oil into the coastline and inland as far as the surge reaches.

Debris resulting from the hurricane may be contaminated by oil from the Deepwater Horizon incident, but also from other oil releases that may occur during the storm.

Where will the oil go?

The spread and movement of oil would depend greatly on the track of the hurricane.

In the Northern Hemisphere, hurricanes rotate counter-clockwise:

Scenario #1: Driving Oil Onshore

– A hurricane passing to the west of the oil slick could drive oil to the coast.

Scenario #2: Driving Oil Offshore

– A hurricane passing to the east of the slick could drive the oil away from the coast.

The details of the evolution of the storm, the track, the wind speed, the size, the forward motion and the intensity are all unknowns at this point and may alter this general statement and how these two scenarios actually play out.

Will the oil slick help or hurt a storm development in the Gulf?

Evaporation from the sea surface fuels tropical storms and hurricanes. Over relatively calm water (such as for a developing tropical depression or disturbance), in theory, an oil slick could suppress evaporation if the layer is thick enough, by not allowing contact of the water to the air.

With less evaporation one might assume there would be less moisture available to fuel the hurricane and thus reduce its strength.

HOWEVER, an approaching tropical storm or hurricane would actually stir up the Gulf waters including the oil.  The oil would likely break into smaller pools on the surface.

This "thinning out" process would allow much of the water to remain in touch with the overlying air and greatly reduce any effect the oil may have on evaporation.

Therefore, the oil slick is not likely to have a significant impact on the hurricane.

Will the oil have any effect on a hurricane?

Most hurricanes span an enormous area of the ocean (200-300 miles) – far wider than the current size of the spill.

If the slick remains small in comparison to a typical hurricane’s general environment and size, the anticipated impact on the hurricane would be minimal.

The oil is not expected to appreciably affect either the intensity or the track of a fully developed tropical storm or hurricane.

The oil slick would have little effect on the storm surge or near-shore wave heights.

Will the hurricane pull up the oil that is below the surface of the Gulf?

All of the sampling **to date** shows that except near the leaking well, the subsurface dispersed oil is in parts per million levels or less. The hurricane will mix the waters of the Gulf and disperse the oil even further.

Have we had experience in the past with hurricanes and oil spills?

Yes and no.

Yes, but past experience has been primarily with oil spills that occurred due to the storm.

There has been no previous experience of a hurricane or tropical storm and an existing oil slick.