Explanation:
What's happened to these clouds?
Normal cloud bottoms are flat because moist warm air
that rises and cools will condense into water droplets at a very specific temperature,
which usually corresponds to a very specific height.
After water
droplets form that air becomes an opaque cloud.
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, being seen near the top of an
anvil cloud, for example.
Resulting mammatus clouds can appear
especially dramatic
if sunlit from the side.
These
mammatus clouds
were photographed last August over
Olympic Valley,
California,
USA.
