True to their ominous appearance, mammatus clouds are often harbingers of a coming storm or other extreme weather systems. Typically composed primarily of ice, they can extend for hundreds of miles in each direction and individual formations can remain visibly static for ten to fifteen minutes at a time. While they may appear foreboding they are merely the messengers – appearing around, before or even after severe weather. ~ Wikipedia
Image Credit
Photo By Craig Lindsay – Wikimedia Creative Commons
Chris Holt says
Yikes….very freaky looking