Bonnie made landfall along the Louisiana coast over the weekend as a tropical depression, with winds up to 38 MPH. How did it impact the BP oil spill? The storm may actually have helped matters, by breaking up the oil. On the other hand, a storm surge - not likely with such a weak storm - could have driven the gooey mess into sensitive marshes.

As for the extensive plumes of oil that are believed to exist deep under water, they will probably not be significantly affected by the storm. Even the strongest tropical cyclone winds agitate only the top few hundred meters of the ocean.

It’s interesting to note the negative feedback involved in this effect. Tropical cyclones derive heat and moisture from the warm uppermost part of the ocean. Yet, the winds cause upwelling of cold water from deeper water. The amount of cooling can be 5°C or more, potentially putting the brakes on a storm’s heat engine.

Those involved with monitoring and cleaning up the spill have been evacuated, so it will probably be a few days before we know anything definitive. For further information on tracking hurricanes, see WDT’s iMap Hurricane.