It depends on what you're near when you go down.
snow may be soft, trees aren't and neither are rocks that could be under the snow. Also, if it's hard-packed, I would think it would be harder than hell when you hit, particularly if you were going fast when you fell. If you can break a leg, you can break your head. I suppose a ski could come off, too, or break and hit you in the head.
Poor Natasha, poor Liam.