I was thinking the same thing the other day. Having a small collection I do have a container for each so I could move them fairly easy. My real fair is loosing power. During the last hurricane that hit Houston I was without power for a week and a half. (Didn't have them then) I guess I would hope that the temps here would be close enough to keep them happy until power was restored. I Guess at that time I would be thankful for humidity.
It is usually warm enough here for them but if it got to cool I would try placing the break open hand warmers under the tanks for heat first. If that didn't work I guess I would have to bring them in container with a fee lamps to work. I'm sure that would go over great.
Being in the emergency service loop I don't get to flee and have to hunker down, work, and try to make it through. Makes my option choices different.