Listing the conditions present following a disaster is not enough. Major disasters create these conditions but the disaster may not be an Apocalyptic situation. To me, the situation created by the disaster is permanent and widespread; not a local disaster that the government can fix.
To define a Post Apocalypse Story, we must first define an Apocalypse. I like the following description:
But what exactly is an apocalypse? Nowadays, we typically think of an apocalypse as a worldwide disaster that can dramatically affect civilization, like war, famine, plague (natural or bioengineered), natural disasters, and nuclear fallout. These scenarios qualify as apocalypses today because they signify to us the very real possibility that life as we know it could end.
For a post apocalypse story, the cataclysmic, civilization-altering event has already ended and life as we know it has changed. In most stories, life as we know it has ended and been replaced by the total collapse of our civilization to include our legal/penal system and our economic system. There are no longer police, courts, prisons, stores, transportation systems, etc. Any food, clothing, weapons, fuel, electricity, operable vehicles, etc., available at the time of the collapse are either a thing of the past or they will be so shortly for the replacement supply chain is destroyed.
The bad guys are no longer constrained by what society will do to them for there is no longer a society to protect the rest of us. The bad guys band together as gangs to take and do what they want. The good guys band together to protect themselves from the bad guys. The good guys have to redefine how they are to conduct themselves in regard to each other and the bad guys. There are no longer police to arrest the bad guys, courts to try them, or prisons to keep them away from the rest of society – so what do you do with them if you take them prisoner. Add in the good guys have to build shelters, if not available, and obtain food and water in the process of defending themselves. Basically the good guys are trying to build a new society, while the bad guys tear it down.
P.S. I archive the posts of many views of PA stories to aid me in writing a story I call The Ark. Part 1, already posted, is what I consider a Pre Apocalypse Story. Part 2 will be the Post Apocalypse half of the story, which I am working on now.