Another Incredible mammatus display tonight following yet another squall line passing through.
Norfolk Nebraska clouds before the storm.... 4/14/2012 "Mammatus clouds are most often associated with the anvil cloud and severe thunderstorms. They often extend from the base of a cumulonimbus, but may also be found under altocumulus, altostratus, stratocumulus, and cirrus clouds, as well as volcanic ash clouds. When occurring in cumulonimbus, mammatus are often indicative of a particularly strong storm or perhaps even a tornadic storm."
Mammatus clouds above Norfolk, Nebraska, 2012
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.
June 5, 2011 | a volcano in the Puyehue-Cordon Caulle chain of south-central Chile erupted after lying dormant for more than 50 years. The government evacuated several thousand residents as Puyehue threw ash more than 6 miles into the sky, pushing the plume toward neighboring Argentina. Authorities had already put the area around the volcano on alert after a flurry of earthquakes earlier on Saturday -- at one point, the tremors reached an average of 230 per hour.
Puyehue Chile, June 5, 2011
Mammatus cloud formations lend the sky an other-worldly appearance.
Home to some of the world's most spectacular weather, the American Midwest has long been the hunting-ground of storm chasers from around the world.
But when a storm arrives, the results can be awe-inspiring. This thunderstorm is a supercell, the largest, most severe class of thunderstorms. The photographer describes this picture as one of his all-time favorites.
It's a game of patience. Chasing will often involve long drives and even longer waits.