Explanation:
Normal cloud bottoms are flat.
This is because moist warm air
that rises and cools will condense into water droplets at a specific temperature,
which usually corresponds to a very specific height.
As water
droplets grow, an opaque cloud forms.
Under some conditions, however, cloud pockets can develop that contain large droplets
of water or ice that fall into clear air as they evaporate.
Such pockets may occur in
turbulent air near a
thunderstorm.
Resulting mammatus clouds can appear especially
dramatic
if sunlit from the side.
These
mammatus clouds were photographed over
Regina, Saskatchewan,
Canada
during the past summer.
