The terrorist attacks of 2001 changed the priorities and focus of federal emergency planners. Former officials say 9/11 diverted attention from naturaldisasters such as Katrina, which had been the primary focus of the Federal Emergency Management Agency (FEMA).
A government document obtained by NBC News shows just how radically the focus shifted to terrorism. It is dated July 2004 and lists 222 upcoming FEMA and homeland security exercises scheduled to prepare for national emergencies. Only two involve hurricanes.
"And even in both of those cases, they're dealing with what would happen if there were a terrorist attack associated with a hurricane event," says NBC News analyst William Arkin.
What's more, it appears that the federal government did not follow up on an exercise last year that mostly predicted what happened in New Orleans — devastating flooding and hundreds of thousands stranded.
The scenario was dubbed Hurricane Pam: 120 mph winds, a massive storm surge, 20 feet of water in the city, 80 percent of buildings damaged, refugees on rooftops, possibly gun violence that would slow the rescue.
"What bothers me the most is all the people who've died unnecessarily," says Ivor Van Heerden, a hurricane researcher from Louisiana State University who ran the exercise.
Van Heerden says the federal government didn't take it seriously.
"Those FEMA officials wouldn't listen to me," he says. "Those Corps of Engineers people giggled in the back of the room when we tried to present information."
One recommendation from the exercise: Tent cities should be prepared for the homeless.
"Their response to me was: 'Americans don't live in tents,' and that was about it," recalls Van Heerden.
However, others say it's unfair to blame the federal government, that no amount of planning could have prepared for this.
"We have trained against similar scenarios, but it's not the same as a crisis unfolding before your eyes," says Frank Cilluffo, a former Bush administration aide for homeland security.
Homeland security officials also argue that no one predicted that flooding and devastation would encompass not just New Orleans but the entire Gulf Coast.