Often during the summer months, meteorologists hear the phrase “heat lightning” quite a bit. “Heat lightning” is a phrase that essentially labels lighting that we see but don’t hear. These occurrences are most often tied to summer storms, because we can generally have evening heat, without sunshine, that fuels nocturnal thunderstorms.
So if it’s not “heat lightning,” then what is it? Simply put, it’s just plain lightning. The reason you see it and don’t hear it is because sound waves do not travel as far as visible light waves. Our eyes can often see what our ears can’t hear.
It can be thought about in terms of geometry. Remember the hypotenuse of a triangle? That is essentially the line that is connecting your eyes to the strike of lighting. For Wednesday night’s storm, our sky cam captured a beautiful display of lightning flashing in the clouds. No rumbles were heard. Our tower cam sat roughly 45 miles from this particular thunderstorm. The storm itself was about 50,000 feet tall. 50,000 feet is just shy of 10 miles. If they sky is clear where you are, and there is nothing impeding your view, it’s easy to spot the tops of the thunderstorms.
The lightning you see, but don’t hear, is producing a lot of lighting where it is originating from. Just remember that. From afar, It can be a captivating sight, seeing all those zigs zags of light flashing against the dark canvas of night, illuminating the perfect silhouette of a storm cloud.