Bombs rain from the skies, alien ships descend with lasers ablaze, improbably proportioned, irradiated sea monsters tear through essential infrastructure. You'd think that running, screaming, and finding clean underwear would top the list of activities likely to improve your chances of living, followed closely by finding a sustainable food source and offering sexual favors to the person with the most impressive arsenal. Unless you were a prepper, in which case you'd be worrying more about the safety of your cigarette stockpile.
Earthquakes, tornadoes, and hurricanes can cause you to leave your home or even be trapped there. Roads could be blocked due to fallen trees, power lines, or even damaged earth from the natural disaster. Rescue crews can not be in all places at once. You may have to wait it out for quite a while before its over. You won't be able to go to the store or to the corner market.