In my past life, I've been an EMT-B and a National Ski Patrol (NSP) Alpine Patroller. You can't imagine how badly people wreck themselves in a ski slope. Broken (upper) back was the worst I've ever encountered, and transported off a hill. Fucking nightmare, not killing the guy in the transport process, to the bottom of the hill, and turning him over to the ambulance-smashers. :o Your emergency kit depends on your skills and training, and your expectations, and your capabilities, and your knowledge, and your will power. Nothing is certain.