I spent several years in the old CD, and played Armageddon Games in the Air Force.
Radiation and fallout patterns/effects were a bit of a hobby for me in those days, before the end of the Cold War...
Don't fear the FALLOUT, fear your NEIGHBOR when the food runs out in 2 days, and his kids start hollering, "I'm HUNGRY!!"...
We don't need a nuclear war for that to happen. Society can collapse in less than a week and that can happen. New Orleans should have served as a gentle reminder of that. Anyone who DOESN'T have at least few weeks of emergency rations set aside is a fool. Better yet, store up 6 months min, gas, a generator,(diesel) medical supplies, and lots of ammo. Why a diesel generator? Because you can make your own dieesel fuel.
Don't fear the fallout.
Fear the radiative / thermal pulse which will ignite all kinds of fun stuff simultaneously for a radius of miles around ground zero.
Just at the same point in time that the roads and infrastructure (necessary to fighting fires) are devastated.