Steve Rose at Daily Kos has more. Further confirmation was had on Larry King:

Joining us now in Washington is Marty Evans, the President and CEO of the American Red Cross. She traveled with the president today. The Red Cross is not in New Orleans, why?

MARTY EVANS, RED CROSS PRESIDENT AND CEO: Well, Larry, when the storm

came our goal was prior to landfall to support the evacuation. It was

unsafe to be in the city. We were asked by the city not to be there and the Superdome was made a shelter of last resorts and, quite frankly in retrospect, it was a good idea because otherwise those people would have had no shelter at all.

We have our shelters north of the city. We're prepared as soon as they can be evacuated, we're prepared to receive them in Texas, in other states, but it was not safe to be in the city and it's not been safe to go back into the city. They were also concerned that if we located, relocated back into the city people wouldn't leave and they've got to leave.