[Cvengr]

That tells me the man and his son were taking or about to take ski lessons, while the girl was not part of the class.

If my kid were in a serene condition, then threatened on the slope by an out of control teen in a calm area, I’d probably jump on the teen also to get them controlled.

If an innocent trusting loved one had been threatened, I can fully understand acting in self defense of his child.

[BykrBayb]

That tells me the man and his son were taking or about to take ski lessons, while the girl was not part of the class.

According to Eagle County Sheriff's Office Lt. Mike McWilliam, she was skiing with a ski school class. Police: Man punched skier on Beaver Creek