Stormy Weather Brings Weird Clouds

If you happened to look up in the sky following Fredericksburg's brush with a severe thunderstorm last night, you might have noticed an odd kind of cloud drifting along. 

Sky-eyed local Twitter user Richard Friesner tweeted this photograph from downtown Fredericksburg around 8:21 p.m. showing fluffy, rounded clouds high up the sky. Friesner, an environmental scientist working at George Mason University, identified the clouds as mammatus clouds. 

According to inscrutable researchers at Wikipedia, mammatus clouds are not only named after mammaries, they are also associated with severe thunderstorms such as the one which blew through the area 20 minutes before the clouds appeared on Twitter. What causes the distinctive mammatus clouds is still up for debate.  Wikipedia article lists 10 possible explanations, ranging from temperature changes to gravity waves to something called the Kelvin-Helmoltz instability, which would be an excellent name for a rock band.