http://offgridsurvival.com/shtfprepperthreats/
Getting from point A to point B might also be a problem. Might have to run a few people over? Might get your car shot up, too; if you even have uncluttered roads you can go down.
I suppose that's not something I personally have to worry about. If I get enough warning, anyway. Not that I'm even contemplating that sanctuary 1000 miles away which would be heaven to some, but Hell to me due to those damn crotch droppings that I'd have to deal with, where throwing them in a stew pot is not an option.