A Supercell Thunderstorm Cloud Over Montana

Is that a spaceship or a cloud? Although it may seem like an alien mothership,
it's actually a impressive thunderstorm cloud called a supercell. Such colossal
storm systems center on mesocyclones -- rotating updrafts that can span several
kilometers and deliver torrential rain and high winds including tornadoes. Jagged
sculptured clouds adorn the supercell's edge, while wind swept dust and rain
dominate the center. A tree waits patiently in the foreground. The above supercell
cloud was photographed in July of 2010, west of Glasgow, Montana, USA,
caused minor damage, and lasted several hours before moving on.