As for the refugees, many of them will be permanently resettled. The people of new Orleans are very poor as is, and it stands to reason that the great majority didn't leave because they either didn't heed warnings and offers of transport or else they never learned of the offers and were without personal transport.

The gov't and the relief services will supply housing. They will be in the Astrodome at least for several weeks. Consider, the children are already being enrolled in local Houston schools.