Mammatus at Sunrise

Mammatus Photo by Craig Johnson taken at Cedar Falls, Iowa

Mammatus Photo by Craig Johnson taken at Cedar Falls, Iowa

This dramatic sunrise is looking east from Cedar Falls, Iowa. Bright yellow light from the setting Sun is illuminating a large field of mammatus clouds. Mammatus form under the anvil of a thunderstorms as air flowing out of the top of the storm is directed downward forming "pockets." Photo taken by Craig Johnson looking east from Cedar Falls, Iowa.