EPOD 20th - Mammatus Above Brookfield

We’re celebrating 20 years of Earth Science Picture of the Day during the month of September! Today’s photo features a popular EPOD from the past. Thanks to all of our followers (on the blog, Facebook, Instagram and Twitter) for supporting us. Thanks also to all of you who’ve submitted your photos. We’re most appreciative. This EPOD was originally published August 29, 2005.

Provided and copyright by: Sheila Halberg
Summary authors & editors: Jim Foster; Sheila Halberg

The photo above showing eerie-looking mammatus clouds was taken just before a severe storm ripped through Brookfield, Wisconsin on August 18, 2005. This particular storm produced multiple tornadoes and torrential rains, causing extensive damage. Mammatus are typically caused by downdrafts of cold air within mature thunderstorm cells. These pendulous clouds don't produce severe weather nor are they always, or even often, a precursor of nasty storms. Nevertheless, when they take the form shown above, they always get your attention.

Related Links:

• Mammatus Clouds
• Types of Thunderstorms
• Thunderstorm Downdrafts
• Life Cycle of a Thunderstorm
• EPOD Archives

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