|Hurricane Katrina, as pictured in the Gulf of Mexico at 21:45 UTC on August 28, 2005.|
The second plot is from Chapter 9 of the draft National Climate Assessment (h/t Kim Knowlton). It's simple, clear and very interesting. The NYT produced a bubble plot using similar data back in 2005:
which more clearly shows concentrations in urban centers, but which gets a little strange looking around New Orleans.
Related: labor market impact of Katrina on evacuees, impacts of Katrina on outmigration and New Orleans housing stock and labor market spillovers of hurricanes generally.