Like Philip in SF/Bay area, SOCAL has earthquakes (which are zero warning, come as you are events) and wildfires which are nice enough to give us some warning. Other areas will have tornadoes and hurricanes (near zero warning vs multiple days warning). You need to consider what those events are and determine the best way for you to prepare. For most situations preps have a lots of similarity -- we all have the same basic needs and rule of 3's applies.

You mentioned a large scary city event where everyone heads home at once. My advice is either be ahead of the first big wave of peeps by maintaining your situational awareness (SA), or being prepared to bug-in your office. I always tried to maintain SA and was able to leave quickly. In that particular office environment bugging in would have been a no-go, so having a boss that said, "go" was very fortunate.