Watch This and Think Katrina
Katrina was the type of disaster where communications were interrupted a great deal. There was marked stupidity on the part of people who were told beforehand that a huge storm was coming and it was well known (I knew it and I don't even live in Louisiana) that the whole New Orleans area was sinking and below sea level and totally dependent on the engineered walls. Instead of getting out, they stayed put. Instead of the local govt using their buses to get people out, they let them stand in the parking lot and be submerged. Instead of taking advantage of Amtrak's offer, which was moving their trains out of the area to protect their holdings, the local govt did not accept free train transportation for the New Orleans citizens.
I think the whole point of this movie and of the real life disaster of Katrina is that you cannot depend on local govt to save you. You need to make plans ahead of time and keep informed about what is happening or about to happen and make wise decisions as soon as possible.
Of course, if a nuclear war started, I think I'd like to be at ground zero and go in the first blast because I would prefer that to radiation poisoning or, even if I avoided that, watching other people suffer.