This horror is really hard to accept. Has anyone said exactly who told people to go to the convention center? I wonder if it was just rumor and word of mouth, since obviously no supplies were routed in that direction.
There's never been a hurricane in New Orleans where folks were without power for more than a day or two. People there are accustomed to leaving town, driving up to Hattiesburg or Jackson, for a day or two, then driving home to clean up the downed trees and resume a normal life.
Nothing in their past experience prepared anyone for this.
(The uncharitable might even add that some degree of common-sense was lacking, but I'll save that for another time)