This group stresses being able to stay alive for indefinite periods in life-threatening wilderness scenarios, including plane crashes, shipwrecks, and being lost in the woods. Concerns are: thirst, hunger, climate, terrain, health, stress, and fear. The rule of 3 is often emphasized as common practice for wilderness survival. The rule states that a human can survive: 3 minutes without air, 3 hours without shelter, 3 days without water, 3 weeks without food. 
The Cold War era civil defense programs promoted public atomic bomb shelters, personal fallout shelters, and training for children, such as the Duck and Cover films. The Church of Jesus Christ of Latter-day Saints (LDS Church) long directed its members to store a year's worth of food for themselves and their families in preparation for such possibilities; but the current teaching advises only a three-month supply.
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.