(CNN) - Mother Nature put on quite a show Tuesday for commuters in Atlanta. Check out these fast moving cloud formations nicknamed “River of the Sky”. The scientific name is Undulatus asperatus.
The clouds form when two fronts meet, but scientists can’t agree if they are caused by a cold-warm front or a dry-moist front.
The ominous-looking clouds are particularly common in the Plain states of the United States, often during the morning or midday hours following thunderstorm activity.