Thunder Horse, the world's largest semi-submersible platform, which was tilting after Hurricane Dennis hit the Gulf, is seen in this photograph taken July 12, 2005.
In addition to flooding and power outages, Hurricane Katrina's landfall on the Gulf Coast may create delays in the area's oil and gas production, which supplies a more than 15 percent of the nation's needs.
Monday morning, oil prices surged above $70 a barrel as the storm approached, and natural gas prices rose 20 percent. Now energy industry officials await reports on whether the storm caused lasting damage to the many refineries and oil platforms that dot the Gulf.
In addition, Louisiana and Mississippi are home to large agricultural and chemical interests, and a major part of the trade flowing in and out of the Midwest goes through the port of southern Louisiana.