It's been over a decade ago, but I've been without power for about a week after a natural disaster. Most places won't open if they don't have power (just because I didn't have power, didn't mean others were without). Not having gasoline and reliable food sources seemed to be the bigger issue. With gas there were long lines, rationing, people still were paying with credit cards. POTs was probably in better shape back then. Cell service was spotty.

From my time working in food service, managing cash has its own infrastructure issues. Secured money bags, blind drops, safes, even a system for counting, tracking, and inventory of cash and coin. Since day-to-day those things aren't used as much I'm sure in a natural disaster it would be a mess.

I'm sure cash with stick around, though.

> Being able to exchange cash for services or goods was super important to preserve life and health.

I think it's super important even in the absence of an emergency. There a number of ways that cash is critical, and for that reason, I don't think it's going to vanish.

Counterpoint: your scenario could be the occasion for people to help each other without money being involved.