This map of where Hurricane Katrina victims have fled to is astonishing. Right after the hurricane, I said to a friend “this is like the Dust Bowl.” I meant that it was a huge social disruption as people relocated to other areas of the country, perhaps entering local job and housing markets and competing with the locals for resources. I know that many of the people who left the area will return, but this kind of mass movement carries tremendous (and largely unpredictable) social implications for all involved.