Moreover, since New Orleans is built on a swamp and is mostly below sea level, once the water breaches the levees and storm walls, the city becomes what amounts to a huge swimming pool for various forms of bacteria, alligators, fish and a multitude of sea life until the water can be pumped out again. My sister went to LSU (in Baton Rouge), and found out all sorts of things about hurricane damage.
These folks definitely need some prayer help and divine intervention.
I lived in NO for 28 years...you are right. They will flood just from the rain, at least some...Bad, bad scene.