Cloud Formation Over New Zealand At Sunset.Undulatus asperatus (or alternately, asperatus) is a cloud formation, proposed in 2009 as a separate cloud classification by the founder of the Cloud Appreciation Society. If successful it will be the first cloud formation added since cirrus intortus in 1951 to the International Cloud Atlas of the World Meteorological Organization.The name translates approximately as roughened or agitated waves.
This is a rare meteorological phenomenon called a skypunch. When people see these, they think it's the end of the world. Ice crystals form above the high-altitude cirro-cumulo-stratus clouds, then fall downward, punching a hole in the cloud cover. Freakishly weird! By Terry Boswell (Joshua Tree Earth & Space Museum)
Asperatus Clouds - Undulatus asperatus is a cloud formation, proposed in 2009 as a separate cloud classification by the founder of the Cloud Appreciation Society. The name translates approximately as "roughened or agitated waves." The clouds are most closely related to undulatus clouds. Although they appear dark and storm-like, they tend to dissipate without a storm forming. The ominous-looking clouds have been particularly common in the Plains states of the United States.
Sometimes very ominous in appearance, mammatus clouds are harmless and do not mean that a tornado is about to form; a commonly held misconception. In fact, mammatus are usually seen after the worst of a thunderstorm has passed.
Tornado in the Making. By The Kav. "I climbed up on my roof-top to get this shot of a swirling cloud attempting to become a tornado. This was at its peak strength in this series of shots...eventually it moved off to the left leaving in its wake some rain and something to talk about the next day! It was an amazing sight in this area which seldom ever sees Tornado's." http://www.flickr.com/photos/the_kav/5951875353