The New Orleans levees were designed to manage a direct hit from a Category 3 hurricane. Had Katrina -- a strong Category 4 storm -- jogged to the opposite side of New Orleans, we would almost certainly have had the "worst case scenario" occur, with Lake Pontchartrain rapidly flooding the entire city and killing almost everyone who remained behind. We've known about this scenario for years, known that was the likely outcome, and decided -- as a nation and as the city of New Orleans! -- to live with it. (The Category 3 decision was made in 1965 following Hurricane Betsy.)
On Monday, we thought that New Orleans was mostly ok and we knew that Gulfport and Biloxi were major disaster areas. Whatever disaster management plans were out there were turning in that direction.
And then there were multiple breaks in the levees. Not even the levees that anyone expected to break, but a wall on a canal in an area that -- if I understand correctly -- had just been rebuilt to strengthen it. By Tuesday, it was clear that New Orleans had arrived in the "hardest case scenario". Instead of cleaning up tens of thousands of dead bodies (which would, indeed, be the worst case), we had to figure out how to get tens of thousands of living people out of an area that was becoming uninhabitable.
I haven't heard about any plans for managing that. I doubt that they ever existed. I'm reasonably sure that if they had existed, Bush and Co. did not grab a lighter when they came into office and burn them.
Should somebody have planned for this? Retrospectively, yes. But 20/20 hindsight is easy. 20/20 foresight is hard.
A friend asked elsewhere why trucks dropping supplies might leave the city without picking up passengers. When you get them to I-10, what are you going to do with them then? We've already got a lot of people there who walked or drove out of New Orleans on their own and we still don't know where to put them.
They're trying to figure it out now. It looks like they're making progress.
I hope they find solutions -- because it's going to take multiple solutions in this case -- soon.