I've used Nik Wax products for years - a cleaner for technical fabrics, followed by a wash in waterproof compound.
I left the mountain shortly after 9:00 this morning, and when I came back over the lunch hour, I met some of the same vehicles heading back down. The school bus is still here, and there are people on the hill.
Decades ago we awoke to a wet day like this, and I called the school to advise them of the weather, and give them the option of cancelling. The teacher said the kids were excited, so they would come anyway. We opened a box of garbage bags, and cut arm holes and neck holes in them for the kids.
Minutes before the buses arrived, the freezing level dropped to just below the parking lot, and the kids had a great snowy day. I don't remember what we did with those holey garbage bags.