Originally Posted by otakushark

Well, supersonic flights were not uncommon in Northern California in those days, so that might be it. Perhaps the streak was a jet contrail, but I don't think that would have attracted anyone's attention the way it did--we were all looking at it before the boom. The streak seemed brighter, and didn't extend back to the horizon. Plus, the streak did not continue past the point where I heard the boom and the ring started to appear.

Do you have any links to pictures of these formations?