|Morning Brief reader Hannah S. wrote in yesterday morning with a request. “We experienced a very intense thunderstorm last night here in Greer, South Carolina,” she said. “There was continuous lightning and what I’ve always heard is rolling thunder. Is rolling thunder an actual weather term, and if so, could you describe it more in detail?” This being right up our meteorologist Ari Sarsalari’s alley, I posed the question to him. Here’s his answer: |
Hey Hannah! So there are a few different things that can cause continuous low, “rumbling” thunder. Sometimes when a slow-moving or stationary thunderstorm is relatively far away (10-15 miles) and it’s producing a lot of lightning, you’ll basically just hear that thunder from a distance … the farther away you are from thunder, you’ll generally hear lower frequencies (more bass-y) than if the lightning was happening very close to you (more of a crackly, powerful “bam” sound).
When you’re far away, the sound has more opportunity to bounce off of terrain, buildings, etc., and that can lengthen the sound of the thunder.
Another thing that can cause rolling thunder is if there is an “inversion” in the atmosphere. An inversion is a thin layer of the air above our heads where the temperature actually rises with height within that layer, rather than getting colder with height. This causes sound waves to bounce back and forth between the inversion layer and the ground and can really broaden and lengthen the sound of each instance of thunder.
Are you curious about any weather terms? Send them in, and we’ll see what we can do to explain them.