A warning shot doesn't put enough distance between an agitated moose and a snowmobiler.
From LiveLeak:
A man, age 51 with a life-threatening heart condition, while snowmobiling out West with his son, comes upon a moose in the wild. Concerned that an animal attack might be about to happen, the site-seeing experience goes bad when the moose, not wanting to be on camera, decides to charge. Coming over the snowmobile, the 1,000-pound bull attacks, kicking the dad in the chest; the moose's intentions were clear...
UPDATE: According to Boone & Crockett, Fish & Game is after this guy.