I'm pretty convinced that this is a smoke ring, whatever caused it (s funny , you d think explosions or something would have been reported in connection, but whatever). The neat thing is that I first saw this story on my facebook feed, as an uber mysterious U.A.P. ring story, but directly below was a video playing, somehow put there by facebook, of a burning man festival smoke ring machine, creating an absolutely identical ring (eventually). The ability to perfectly replicate sightings can be seen as legitimate debunking. So, it'sstrange that facebook instantly debunked the story for me.