Lots of flooding in Iowa, and it looks like a mess. But it is most notable for its lack of mayhem and looting, in contrast with Katrina, which was like the second floor of a frathouse party, people operating without a super-ego. I think this is what Steve Levitt would call, a natural experiment. What is the difference? Population density? Poverty rates? FEMA's response? The state's response?
The standard narrative on the Left is that Bush's incompetence and indifference was a primary cause of the social meltdown observed in Katrina's aftermath. I think that gives the President way to much blame. A comparison with these other disasters would be a good Master's thesis.