This would be an interesting analysis to develop levels of SHTF... Level 1 is an economic depression or a large area natural disaster. Eurozone breakup. Stock market crash. Level 2 is something we haven't seen recently and needs to be worldwide. A deadly plague, WW III (conventional), A food shortage that hungers over 1 billion more people, an energy shortage that turns off power for 1st world countries for extended periods of time (not rolling blackouts or temporary), many governments fall simultaneously Level 3 is doomsday level stuff. Local nuclear exchange. A massive sun flare that wipes out satellites and electricity worldwide. Collapse of world trade. At least a billion dead in a year. Level 4 is human race survival SHTF ...zombie apocalypse, alien invasion, Noah's worldwide flood, dinosaur meteor, ice age with glaciers down to Mexico. Multi-Billions dead if not everybody. This topic deserves more thought than a couple minutes. I think doomsday preppers should come up with a standard level one to five levels. That would be useful to a lot of people! Then after defining the levels you can identify what sort of preps you need to do to be prepared for that level.