Why is some thunder longer than others?

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Why is some thunder longer than others?

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There are a few factors here. Thunder is created when lightning zips through the air, causing a sudden heating up of the air, that causes a blast wave to go out from that point.

Not all lightning is straight down from the clouds. Some of it kinda does a zig zaggy thing which will cause longer thunder. But also, sometimes there isn’t a single strike. Sometimes there are 2+ strikes all within just like 1 or 2 seconds in the same area. So this action causes several waves of thunder to be really close in time to each other. So you hear it as a longer rolling thunder.

The other thing that can happen in a very active storm is that a lightning strike can happen way off in the distance and then one closer a couple second later, so the sound waves hit your ears pretty close together. So they sound more like rolling thunder.

The duration of thunder can be affected by the shape of the lightning bolt that created it. When a bolt strikes, different parts of it are at different distances from you. The top of the bolt in the clouds is likely further away from you than the part striking the ground, and bolts may be in various directions, may zig-zag and fork. In any case, all those different regions of the bolt superheat the air they touch, creating thunder. You’ll hear the thunder from the closest part of the bolt first, and it’ll rumble along until the sound from the furthest point reaches you.

In short, thunder will be longer as the distance increases from the closest point of the bolt to you and the furthest.

Now riddle me this: While living in New Mexico I experienced some REALLY long-duration thunder… 4-5 minutes at least! It was all local to me (or seemed to be). The sound was not terrifically loud. It seems unpossible for a single lightning bolt to last that long.

It really depends on the distance to the lightning strike, length and duration of the strike, and shape of the terrain. The high frequencies weaken faster than low frequencies, so distant thunder sounds lower-pitched. As other comments have said, you’ll hear the sound from different parts of the strike at different times, so the sound from a long bolt will last longer overall when it reaches your ears. The shape of the ground and the amount of cloud cover all generate echos, further stretching out the sound of the thunderclap into a longer, low roll. MinuteEarth did a great [video](https://youtu.be/D3_w2sUPItY) about this last fall. Check it out!