Have you skied before? In my experience falling onto gear isn't as much as a problem as some people here seem to think. I've just come back from a week skiing. I carried a phone and a GPS, and fell several times, without them hurting. I wore a jacket with chest pockets. In a fall that area tends to be protected by my arms, and/or curling my body around it.

I carried less than I have done in previous years, and not much more than my usual EDC plus ski clothes. The GPS is fun because it records maximum speed and my tracks - it reckons I was doing over 60mph at one point. I did carry a 350ml pouch of water and a Snickers bar, which I don't EDC. I wouldn't leave my phone behind. Coverage tends to be good in popular ski areas, and phone + GPS is usually enough to you rescued. (I'm not saying to rely on this, just that it is the best first resort and better than spending a night on the mountain side.)