Fireball appears on Rocky Mountain ridgetop in May 2013.At approximately 0115 on the above date, I was sitting on my south deck in the central Rocky Mountains, at an altitude of about 9000 feet, when I observed a fireball which resembled a crowning forest fire moving from treetop to treetop on a mountaintop some three miles to my south.The nearest neighbor to the apparition is a retired fire chief. I asked him if he made the same observation. He replied that he was asleep at the time.The fireball appeared to be about forty feet in diameter, round in shape, and fiery yellow in color. It disappeared as mysteriously as it appeared after about 20 seconds.No forest fires were reported in our area for weeks before and after this strange object was sighted. Neighboring cattle, elk, cougars, bears and other wildlife did not appear to respond to the fireball. I am a combat veteran, and can assure the reader that the fireball resembled no military ordnance detonation or conflagration.The next morning there was no visible evidence of burned vegetation on the ridge.