Oh, great. Not only it might clobber Louisiana, but it will definitely shut in
Natural Gas and
Oil on the Gulf Coast. We may see $70 per barrel oil.
Hurricane Betsy caused a levee to break in New Orleans in the 1960s, and people who lived through that have stories to tell.
In one case, a family had to get on the roof of the house because any lower point was in water.
The people had to fight critters and creatures for the roof -- snakes and other things wanted the high ground. It was very unpleasant from what I remember of these stories.
Oh, great. Not only it might clobber Louisiana, but it will definitely shut in Natural Gas and Oil on the Gulf Coast. We may see $70 per barrel oil. If Hurricane Katrina hits the New Orleans area directly it could cause a MAJOR disruption of petroleum supplies given the massive amount of petroleum facilities southeast of the city. The very possibility of the very first scenario from the fictional movie Oil Storm--where a major hurricane severely damages a large fraction of US petroleum capacity--could become a frightening reality. 
The possibility of oil reaching US$80 per barrel could happen--and the US economy screeches to a frightening halt, with the possibility several large airlines going out of business, starting with United Airlines and Delta Airlines. 