When you started your post with "I was snowboarding in the alps....." I could see something happening. Those kind of statements usually do not end well for camera gear.
The first words that occurred to me were, "Chest harness."
Agreed. I thought back pack. I do not see any reason to have a camera on a strap when you are snowboarding down the mountain. Better to keep it all wrapped up, stop and get it out (seconds only) and shoot. Much better than what happened, or potentially falling and damaging it and you too. Live and learn I guess.