I just wanted to comment about an important thing that people need to remember (mistakes happen more often during stressful times): some of the advice given here have to be done AFTER the blast and the aftershock, not BEFORE them. You have to use the few minutes you have to get all the gear you can muster in such a short delay and run to the shelter you want to hide in.
It isn't hysteria, and GMO isn't 'evolution'. One of the biggest issues for preppers and survival is that GMO seeds will not reproduce in the same way if the seeds are saved and re-used. In fact, in many instances (maybe all?), it's illegal to save the seeds and re-use them! It's far better to track down heirloom seeds that are native to your area and/or compatible with your climate. A good place to start looking is ×