The main cause of the heavy loss of life from Katrina was that New Orleans' emergency plan for a flood was incomplete and inadequate and their implementation of this plan was a cluster f***. Maybe we've reached the point where all local emergency plans have to be approved by FEMA (because of incompetent local officials), but at this time that isn't required by law.
The overwhelming disaster of Katrina will hopefully institute passage of workable laws interlinking the different portions of governmental response efforts.
The next challenge may unfortunately be brewing off the Florida coast right now, since Tropical Depression No. 16 is expected to become Tropical Storm Ophelia. Data
Florida's 'Coming' Hurricane Calamities
Note the date of this Miami Herald news article; July 22nd 2002.