Have your items ready in case you DO decide to evac, so you can stuff him in a bag, grab up a tote and go, without having to gather items. Remember to put his paperwork(if you have any) in a ziploc and drop it in the bin too, then you don't have to worry about it.

If you don't have to evac, watch the temps in the cage. If it's too hot in the cage, you can bag him and bring him out to a cooler spot. Don't feed him. Mostly you have to watch for overheating. If it were winter, you can heat water on a grill and make hot water bottles for a snake, but that shouldn't be an issue right now.