I have no idea what lead up to this, but violence is never an acceptable answer to on hill disputes. Clearly the blonde haired girl was out of control and way way out of line.
Dodgy territory trying to breakup fights when the opposite sex is involved but I wish someone had stepped in sooner and come to the aid of the girl who was trying to defend herself while still strapped into her board (pretty low down to maneuver by the blonde to try to scrap while she still had one foot in). I sincerely hope the brown haired girl is no worse for the wear and the blonde girl is at the very least banned from the mountain.
* Video courtesy of @deguzmanalex