Mammatus clouds Pouch-like protrusions hanging underneath the base of a cloud. Usually form under cumulonimbus clouds due to sinking air pockets.

The 29-year-old administrative assistant's viral video of the terrifying sight shows the giant cloud mass on the horizon and the sky suddenly turning dark over Raposo Tavares Highway.

This is the terrifying moment gloomy storm clouds swirled over homes in Maryland. Dramatic footage captured by Tim Grooms shows a twister forming before touching down near Tall Timbers Cove on May ...

A strong geomagnetic storm could be caused by a recent coronal mass ejection from the sun.

Images of dramatic green skies and ominous rain clouds were snapped on Tuesday as a series of severe storms approached Sioux Falls, South Dakota.