...So what would you folks carry to prepare for a huge, regional, urban/suburban disaster that hits in seconds without warning?
A healthy supply of mindfulness and situational awareness.
Be careful with trying to prepare for every contingency, it'll drive you nuts (been there, still do that).
Pick the
most likely scenarios.
Prep to cover that.
Have a back up plan.
Stay flexible.
Don't panic.
That should cover most things.