I don't think you have to be prepared for a specific scenario. It would be like asking why someone carries concealed, for muggings, carjackings, assaults.... I carry concealed for all those reasons and any other reason that might require using a gun.

Same thing for being prepared for a disaster. Being prepared if you have to stay home for a few weeks, or leave for a few weeks. A decent firearm, some food, water and medical supplies and then a long term plan on how to keep replenishing them as needed.

As to which cause of a disaster is more likely, all of them are extremely unlikely....

Cameron