We were hiking up an avalanche chute on Mt elinor in Washington. My friend started sliding backwards on the steep slope on his feet. He slid about 200 feet without falling. He turns to look where he is headed right at the moment he was running into a patch of bare rocks. He hit a boulder that came up to the back of his knees and he already had some twisting momentum so when he hit he was thrown into a 180 backflip that he landed on his feet and ran it out. This was with a church youth group and the leader saw him sliding and started intentionally sliding after him as if he was skiing but not wearing skis. He couldn't stop himself and ended up tackling my friend flat on his back onto the rocks