It won't happen. People are required to do what they can, yes. But ultimately such an even is in the hands of God. And despite appearances, God still loves us.
My dad freaked out and moved us over the horizon from San Antonio, about 35 miles away from the city limits into a rural area that would have little to no fallout from prevailing winds back in 77’. Everybody that was in my dads department did the same with their families.
He also said God would be having nothing to do with it.
FYI, anything east of the Mississippi has already been irradiated from the above ground tests. That’s why cancer is so prevalent on the east coast. Strontium will be there pretty much forever. Anyone that has had a lifetime radiation exposure maximum limit is told not to ever go there.