IMO red is clearly at fault. I’m not really interested in debating who is ahead of who or other details. I’d rather focus on what should be done by both skiers to be safe.
What the red skier should have done:
1. Red saw grey for an extended period of time and should have taken care to safely pass grey. Red should have taken care while he was behind, while he was even and maintained care until he was significantly beyond grey (at which point we can be pretty sure grey knew red was there)
2. If at any point while passing, the skiers got close to each other, red should have slowed or stopped to avoid collision. Also, if red lost track of where grey was, he should have decreased speed and move away from where grey generally was.
What the grey skier should have done:
3. Grey should have maintained a better lookout if at all possible. Grey’s primary responsibility is to avoid skiers further down the slope so his ability to look back is limited. However, if no risks were ahead of him, he should have taken care to look around.
3b. When grey began going across the slope, he should have known that his action increased the risk of collision and it would have been wise to look across at a minimum and even up the slope if feasible.
4. If at any point grey became aware of red’s dangerous proximity, grey should have turned, slowed or stopped to avoid collision.
Clearly I am harder on red than grey but IMO that’s warranted because red knew he was passing grey whereas grey did not (or at least did not until things were already very dangerous). Red had 15 seconds to evaluate and avoid collision; grey had only a couple seconds.
I am very much not in favor of the concept of lanes since it could promote aggressive skiing and justification for collisions. I do agree that skiers taking wide turns should take extra care since these turns increases the risk of collision even if it’s not their fault.
If safety is in doubt, I hope we at Epic will promote slowing down and leaving bigger gaps between skiers.