It's remarkably hard to plan for one without any idea of the "shape" it would take. Region vs. region? Faction vs. faction, which would geographically mix it up a lot more? What would which governments be responsible for, and not?

The normal preparations would go some ways, everyone should have bugout plans, storage of food, water, essential medicines, etc., and while of course not recommended by most governments, basic arms, e.g. a rifle and pistol. Beyond that, it's really hard to say at this point, especially since we seem to be so far from one (for how long did our only Civil War brew?).

Civil war would be somewhat out of the scope of what the article is talking about, namely discrete, punctuated events like nuclear blasts and earthquakes. Even hurricanes last only a few days in one area. War could drag on for years.

One can typically see a civil war coming from much further away than a hurricane or earthquake.

Civil war in the west is just not going to happen. There is localised political violence, but a proper civil war requires the defection of some or all of the military. The most likely country for this that counts as "western" is Turkey.