Originally Posted by
Genghis the Engineer
Anyhow, I happened to be looking at a clock when half an hour ago there was a lightning flash. 3ish seconds later I heard the thunder - which then carried on (decreasing in loudness steadily) for a good 45 seconds. It did the same several more times over the next ten minutes.
So what was happening here?
Is the lightning event rippling down the length of a chain of embedded CBs?, or is this some accoustic effect causing a steadily decreasing echo?
Acoustics. The thunder first arrives from the closest point of the lightning bolt - but then the thunder arrives from the more distant parts of the bolt. After all, the lightning bolt is not an arc of a circle with centre exactly at you!