Mammatus Clouds Over Tomahawk, Wisconsin
June 06, 2007
The photo above showing a particularly conspicuous example of mammatus clouds was captured over Tomahawk, Wisconsin in June of 2002. The sulphur color of these pendulant clouds made the entire sky appear quite surrealistic. Mammatus are apparently caused by downdrafts of cold air within mature thunderstorm cells, and they most often occur on the underside of a spreading cumulonimbus anvil. Their daunting looks get our attention, however, they're not an indicator of impending violent weather.