This is just a tragic story.

This is the official statement from the Gallatin County Sheriff's Office:

Yesterday on July 24th we received a call at 3:18 PM about an 18 year old male who collapsed while riding his mountain bike up at Big Sky Resort. The Big Sky Ski Patrol responded quickly to the scene and continued life saving efforts that had already begun. The male was moved to a suitable landing zone for the Reach AIR landed and assisted with life saving efforts. The male was transported to Big Sky Medical Center but did not survive.

This is a truly sad story. For the whole statement, go to the Gallatin County Sheriff's Office website.