For the sake of argument - what if they had mentioned breached levees - not just overtopped levees in these briefings? When the briefings occurred there was concern about a Cat 5 direct hit which didn't happen. And take it further. If they were discussing breached levees and such a catastrophe - why weren't all of the people evacuated earlier? This makes the locals look even worse.
And look how everybody complained about Rita, when the evacuations were ordered well ahead of time, and you had all of the traffic jams and people running out of gas on the highways.