Phase One: Within the first 3 hours.
1. Watch and listen to all media coverage (TV, Radio, Internet) to assess not only the gravity of the situation, but where it began, and how close it is to your area. Also keep a battery-operated radio nearby in case of power-outage.
2. Contact all nearby loved ones (within 15 Kilometers, so that traveling is short-distance), so that they may grab a few things, then regroup in one single, safe location of my choice.