Mammatus clouds at sunset, over Idaho

Mammatus 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.

View larger. | Mammatus clouds at sunset submitted by Andrew Ashton in Nampa, Idaho.  Thanks, Andrew!

View larger. | Mammatus clouds at sunset. Photo by Andrew Ashton. Thanks, Andrew!

Andrew Ashton in Nampa, Idaho submitted this beautiful shot, which I believe he captured earlier this week. The pouch-like protrusions hanging from the undersides of these clouds are called mammatus clouds.

One interesting aspect of mammatus clouds is that they’re formed by sinking air. Most clouds are formed by rising air. They typically indicate stormy weather, but, contrary to myth, they don’t continue extending downward to form tornados.

More photos: You’ve got to see these mammatus clouds

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Deborah Byrd