Have you ever seen a roll cloud? It’s a gentle version of a gust front or shelf cloud that we see in thunderstorms, except you don’t need a storm for a roll cloud to form. Unlike a shelf cloud, the roll cloud is not attached to anything. All it takes is a little push of moist air into calm air that rises just enough to condense and form a cloud. If you watch it in fast motion, you would see the rolling motion of the cloud.
The video was captured in Foley, Alabama by Crystal Harden on April 12, 2017.