Mammatus clouds, the bubble-shaped protrusions sometimes seen underneath cumulus clouds, are a rare and dramatic type of cloud. The mammatus is typically short-lived, with lobes lasting only 10 minutes or so. Their rarity and short appearances are among the reasons why this cloud type has been little studied. As a result, there are many theories as to how the clouds form their distinctive, bulbous lobes, but, to my knowledge, there is no single widely accepted explanation. Mammatus often appear before or after severe thunderstorms and are associated with strong turbulence, so this may play a factor in their formation. (Photo credit: C. Lindsey; via APOD)
Mammatus Clouds
