When I saw the title, I thought it was a regular fall while skiing which is not really bad as you need to be unlucky to get injured from a ski fall.
This is different though. He is trying to do a stunt which is really not cool given that he does not look like he is a good skier (skiing down that slope, he does not have a good form unless he was not trying) and falls like those can be really bad. I am surprised he attempted it. Was happy to see the skies come off though...worst case scenario is for the skies to stay on during a fall...that's how all the bad knee injuries happen.
Yes, I know quite a bit about skiing...and am surprised he would try such a stunt, even though the slope looks mild, it's too large a risk for my liking.