25 year old freestyle snowmobile rider, Caleb Moore, has died following his injuires after a crash last Thursday during the Winter X Games. 

Moore was attempting a backflip in the freestyle event in Aspen when he landed face first in the snow and the 450 pound snowmolbile rolled over him.

He actually walked way from the crash and went to the hospital for a concussion but then Moore developed bleeding around his heart and had to undergo surgery. The family later said that a compliciation involving his brain caused his death.

Source: USA Today