When my friend had to evacuate because their house caught on fire in December they had to stay in a place with no electricity that was very cold, so she ended up grabbing some of the heaters she used to ship her animals with. I think she wrapped them in a towel and put it under the tubs, and I also remember something about insulating them in some way. It was something about warm water bottles or something.. One of the more sensitive ones she packed up as if she was shipping him for the move over in the snow. It was a ridiculous event. But at least it kept her snakes/geckos/frogs alive in snowy weather!

But since you get to be in a place with electricity, sounds like you have a much easier time and some good advice!