id be hesistant to recommend it. bone loss occurs steadily after age 40-45 or so. falls are a part of skiing and snowboarding and can cause fractures in even young people.
If a person has been active and relatively healthy habits all their life, its not much of an issue. The current thinking is if a child is active and doing some bone jarring activities they develop higher bone density than a couch potato kid...and that the higher bone density is a boone later in life.