Tuesday, July 14, 2015

The Cause of "Heat" Lightning




 Have you ever been sitting outside on a hot & humid day and noticed lightning off in the distance? Chances are you thought it was Heat Lightning!  And you'd be right..for the most part!
Except, that lightning strike you saw isn't actually caused by heat. It's a lightning strike from a storm off in the distance! The reason you can see it is because light travels faster than sound.
 
In addition, the sound waves from the thunder that would accompany that lightning strike might get held up by the Earth. As you go higher in the atmosphere, changes in air temperature and density will affect the propagation of the thunder sound wave.
 
Meantime, as the sound wave travels along the surface, the curvature of the Earth will also refract the wave into the atmosphere.
 
So, the more distance between you and the lightning bolt, the better chance of a distorted or even absent clap of thunder!
 
-Brendan Johnson
FirstWarn Weather Intern
 

No comments:

Post a Comment