Hi, sorry if this is a dumb question. Dd1 is off skiing with the school in half term, and part of the list is a bum bag as they don't want beginners with rucksacks. She's scoured etsy and has found some she deems acceptable, but they are cotton canvas. I would have thought she needed something waterproof, but would it be under her jacket? I'm sure it would be (hence feeling a bit dumb here), but am not entirely sure. I don't really want her purse etc getting soggy.