Assume the airline crash position; tuck your head between your legs and kiss your you-know-what goodbye. <img src="/images/graemlins/shocked.gif" alt="" />
(Just kidding.)
It's gonna be chaos, however you look at it. But look at New York City on 9/11. You would think such a horrible act of terrorism would have spawned a total breakdown. Instead it was Mother Nature last year that managed that.
I think it's safe to say you can't predict how things are going to go. To me, the best idea is to try and take care of yourself and your family, along with finding a good location to ride it out. Getting to that location is probably going to involve a walk/hike, so have some good boots!