ST. LOUIS (KTVI) – We’ve likely all heard of the term “heat lightning” on a summer evening when those strong bolts of electricity can be seen, but there’s never any thunder to follow. What many don’t know is that there’s actually no such thing.

Usually, the idea sparks from the thought that heat can trigger lightning, as it’s most commonly seen in the hot summer months.

To put it simply, that lightning you see is part of a storm, and you’re just too far away to hear the thunder or see the lightning fully. The Farmer’s Almanac noted that when there is an intense thunderstorm, lightning may be visible up to 100 miles away due to the reflection.

“Often, mountains, hills, trees or just the curvature of the earth prevent the observer from seeing the actual lightning flash. Instead, the faint flash seen by the observer is light being reflected off higher-level clouds,” according to the National Weather Service.

Thunder can only be heard within a 10-mile radius from the lightning strike; however, if you’re listening to an AM frequency radio, static may be heard.

Always keep in mind that if thunder can be heard, you are close enough to be struck by lightning. As the saying goes, “When thunder roars, go indoors.”