system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: why does the sound of thunder come in successive booms?

Okay, bear with me.

I’m sitting outside watching a thunderstorm, and I see a bolt of lightning flash. I do the counting thing, to tell me roughly how far off it was, and it finally came back at 4 seconds. But then it kept going for another second or two.

I understand how the sudden burst of energy causes the hot air to rush away faster than the speed of sound, but I’m curious why we don’t just hear a single boom?
gpt
The average lightning bolt is five miles long. That means that for any given bolt you are unlikely to be equidistant from every part of it, meaning we would expect the sound to be drawn out to some extent. Another factor is that the sound will bounce off large features such as hills and mountains, again extending the sound by echo into a longer rumble.