I basically would do the same as mommanessy said only I use pop bottles easier to find. The other thing is make tags with you name and contact info the latin name of the snakes (pythonidae regius) and common name (Ball or Royal python) A good base line temp (84-88 pick one I use 87ºF) noted as safe temp and humidity (60% humidity) And harmless captive bred snake noted in the largest letters. You may not be allowed to take animals with you.
You might also go and contact the DARTS (disaster animal rescue team) before it sets in and check what the emergency provisions are for your area. Can you take animals with you can they go to the shelter? and any advise they have. In my area they are super helpful and if you inform them where they are and what they are they can actually make note of it and make special provisions to keep them nice and comfy during the evac.
They are associated with Hsus but in my area they don't pay any attention to politics of that and just stick to the motto. 'from harm to home'