erratic vapor trail accompanied by an explosion was witnessed by me in my SE sky at around 15:10 ASTon Monday, Jan. 29 ((sic December??)), I was snow-shoeing about a mile NE of my home and had turned to face the mountains to my west at the mouth of a small creek that empties into the Tanana River. When to the Southeast and approximately 75 degrees above the horizon I witnessed and erratic vapor contrail that dropped in several loops terminating in a rather large vapor cloud, with small vapor trails dropping from the terminating cloud. Several seconds later there was a "echoing" boom, somewhat like a sonic boom when an aircraft breaks the sound barrier. I thought it was a high altitude jet or a rocket that had gone out of control, so I rushed home as fast as I could and called my wife to come out and look at the vapor trail that was slowly dissipating to the ESE. The trail was still in sunshine yet and was visible for about 25 minutes in the fading daylight.((NUFORC Note: Many news reports published in Alaska about this incident. The object probably was not a meteor, if the sonic report followed the sighting by only a few seconds. We do not know what the object was. PD))