Try this: Put on your winter gloves, climb in the the shower, turn the water on ice cold, and see how well you are able to operate your iPad.

At least with paper maps and a #2 pencil, you have a fighting chance in those conditions.

My phone works fine in the rain. The touchscreen is garbage, because it can't differentiate my finger from a puddle on the screen. Granted, there are pressure sensitive touchscreens out there. If you want a good map that you can take notes on, you'll need a custom app. In my experience, writing on screens is very fussy business. So you might be able to a custom app, custom hardware, maybe spending thousands per unit.

But, paper. I mentioned a brand name. It's wonderful stuff, nothing like the paper you're thinking of. This solution costs a few bucks per person.

https://www.riteintherain.com/

Edit: this "rain" crap is a digression from the "fire" problem. I don't have experience there, but I imagine "the electric infrastructure and cell towers burnt down" is more of an issue... again, paper and pencil wins.

Nowadays decent hiking maps are made of Tyvek or a similar material so they're waterproof. A water resistant device works too but not as well when there are raindrops on it. I guess the moisture messes with the capacitive screen, the device can also stop working at a really incovenient time. That can't really happen with a regular map.