I do the math over and over. In NO alone, with a population of 1.4 million, the report is that 400,000 left before the storm. They have maybe 200,000 in shelters or waiting on buses. Where are the remaining 800,000?
The 1.4 million figure is not for the City of New Orleans, it is for the whole New Orleans metropolitan area. The population of the City itself is a little more than 1/3 of that figure. There are a lot of folks left in Jefferson Parish and other places who don't need to leave because they aren't underwater.