Mammatus clouds are pouch-like protrusions hanging from the undersides of clouds, usually thunderstorm anvil clouds but other types of clouds as well. Composed primarily of ice, these cloud pouches can extend hundreds of miles in any direction, remaining visible in your sky for perhaps 10 or 15 minutes at a time. People associate them with severe weather, and it’s true they can appear around, before or after a storm. Contrary to myth, they don’t continue extending downward to form tornados. These clouds can appear ominous. But, in a way that’s so common in nature, their dangerous aspect goes hand in hand with a magnificent beauty.
Photo by EarthSky Facebook friend Karen Slagle. She wrote, “I took this image Saturday evening May 25 south of Amarillo, Texas.”
View larger. | Mammatus clouds over Ft. Worth, Texas on May 20, 2013 – the day an EF5 tornado struck the suburb of Moore, near Oklahoma City, killing 24 people. Photo by our friend Sundog Art Photography. Visit his page on Facebook here.
View larger. | Pam Rice Phillips caught the same mammatus clouds as in the image above, on May 20, 2013, the day the tornado struck Moore. She’s in Granbury, Texas, which is southwest of Ft. Worth. Thank you, Pam.
View larger. | Mammatus clouds over the North Sea, as seen from Tynemouth, England on May 22, 2013. Photo by Colin Cooper.
Mammatus clouds over Salt Lake City, Utah on May 29, 2013 from Shanna Dennis. Thank you, Shanna!
Mammatus clouds over Denver by EarthSky blogger Larry Sessions. June 15, 2012.
Read more about how mammatus clouds form from the Weather Channel
View from space: Four satellites views of Moore tornado
Bottom line: Three photos of mammatus clouds, taken from May 20-22, 2013.