You could pre-pack your snakes when there is a severe weather warning- it's very time consuming, & that's something that worried me when I lived elsewhere, under threat of wildfires, as that's another thing that doesn't give you much time to pack. You're wise to at least try to plan ahead. Chemical-air quality issues- not sure what you could do for that, as everything has to breathe, & the last time I checked, none of my snakes would keep their little masks on...