What caused the stunning phenomenon?
Residents of Iron Mountain, Mich., were treated to an extraordinary display of bulbous-looking clouds on Monday night. The phenomenon was captured by Joe Nottage, who posted the image on Facebook and asked, “Can anyone explain this?” Meteorologist Jeff Last tweeted the photo and wrote, “Mammatus in Iron Mt, Mich this evening. Taken by Joe Nottage. #miwx pic.twitter.com/83lsFPlBtw.”
What caused the formation of the ball-like clouds? As Last noted in his tweet, these are actually mammatus clouds, a pattern of pouches bubbling beneath the base of a larger cloud. Mammatus clouds may look ominous, and sometimes they foreshadow trouble. In fact, mammatus clouds can indicate severe thunderstorms are imminent. The clouds form following sharp gradients in temperature, moisture and wind shear, and can extend for hundreds of miles.