I had a friend who lost his house in New Orleans. I helped him get his things almost a year after the hurricane. His uncle was a New Orleans Firefighter and assisted. When I went, there were boats on top of buildings and the place still looked like a war zone as well as a ghost town. We stopped and talked to a police officer about it, he told us over 200,000 homes had to be destroyed because of black mold was growing everywhere.
It just had me thinking, what if something like Katrina had happened nationwide ??? Or even continent wide???
The people in the worst parts of New Orleans were rescued because they had left. If something such as an EMP were to hit, or severe solar storm, the effected area would be so large that you would not be able to just get up and leave.
Just playing devil's advocate
The disasters mentioned in the above posts are good examples of what happens to small localized catastrophes. But what if the catastrophe is not small nor localized?
I am sure the National Guard would be deployed to worst effected areas with the highest population. But ... would they react the same way as New Orleans?
There has been a lot of discussion on this and it has been very insightful ... thanks for all the feedback.