Evacuation ordered after levee breaks
The Christmas estimation, even for devastation of this scale, is defeatist. Once the levee is plugged and the water is pumped out, which will take a few days/weeks, people will be able to return to what's left of their homes. Cleanup will likely be ongoing through the fall. Rebuilding, however, will take many years for New Orleans and the rest of the gulf coast.
No doubt New Orleans will continue, but it will take decades for the city to recover from this blow. Tens of thousands have been displaced, and who knows how many will take the insurance money and just move?