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Why some lightning storms boom and others rumble

Meteorologist explains different sounds of thunder

David Chernitsky captured this picture as the storm passed World Golf Village
David Chernitsky captured this picture as the storm passed World Golf Village

JACKSONVILLE, Fla. – Have you ever wondered why thunderstorms quickly boom while at other times rumbles? 

Listen closely during the next thunderstorm and perhaps you will hear the song of a storm.   The dramatic boom of thunder is not just one note but a chorus of crackles and rumbles.

The variety depends on your distance from lightning and if the bolt stays in the clouds or strikes the ground. 

CG strikes, or cloud to ground, lightning usually creates louder thunder than CC, or cloud to cloud lightning.

CG lightning can be very close with a flash and then near instant bang sound. 

Shane and Deidra sent this photo on Storm Pins of a radiant cloud to cloud lightning burst near Neptune Beach
Shane and Deidra sent this photo on Storm Pins of a radiant cloud to cloud lightning burst near Neptune Beach

The flash always comes first. Next, heated air rapid expands and collapses triggering a shockwave thunderous clap.

Sound travels at 750 mph, much slower than light, which helps you determine your distance from lightning. Just count the seconds after a flash. Every five seconds equals 1 mile.

The pitch of thunder changes depending on your distance from the flash. High pitch booms come from nearby lightning but distant thunder sounds deeper with lower rumbles.

Because of air density dampens out higher frequencies, your ears only hear the lower frequencies propagating through the air.

Longer rumbles come from lengthy bolts in the sky over several miles long. Sound waves traveling from the front and back part of the lightning channel reach your ears at different distances staggering the rumble sounds over several seconds.

This is especially true in CC charges when the lightning channel is roughly parallel to the observer and can extend over 15 miles.*

Remember, no matter how far away you see lightning, if you hear thunder, you are within striking distance.

*The record for the longest single flash of lightning ever recorded reached 199.5 miles in length, roughly the distance between New York City and Washington D.C over Oklahoma in 2007.


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