Actually, everyone anticipated a Class 5 hurricane, and the news on sunday night, as Katrina's image filled the TV screens, was followed by extensive speculations with diagrams of filling up the soup bowl that is New Orleans. So I don't know why they were no prerpared.
Anyway, here is the quote from Bush via Wash. Post.
Exodus From New Orleans Continues Amid Chaos: "'But given the fact that everyone anticipated a possible hurricane 5 hitting shore,' Diane Sawyer asked him, 'are you satisfied with the pace at which this is arriving and which it was planned to arrive?'
'Well, I fully understand people wanting things to have happened yesterday. . . . I mean, I understand the anxiety of people on the ground. . . . I don't think anybody anticipated the breech of the levees. They did anticipate a serious storm. But these levees got breached and, as a result, much of New Orleans is flooded and now we're having to deal with it and will.'"