You know the drill- it’s humid outside, you look
towards the sky and find some angry clouds approaching looking dark and
elongated. There is bound to be some rain and possibly some severe weather. We
all know what Mother Nature has in store for the near future. Some may flee at the
sight and some bask in the drum these clouds will make. Although, what are
these large and dark appearing clouds? Cumulonimbus Clouds.
These storm clouds come from the Latin words
cumulus “heaped” or “pile” and nimbus “rain”. They can rise up to about
12,000 meters or 39,000 feet, and form in unstable atmosphere. They are created
in three stages: the Cumulus stage, the Mature stage, and the Dissipating
stage. During the Cumulus stage the Cumulus stage, warm moist air (or thermals) rises
through an updraft. These thermals will continue to rise, cool, and condense.
All the clouds need is to continue growing in some forcing triggers. These
triggers can come from ascending up a steep incline, a frontal boundary,
convergence, turbulence or simply warming the earth’s surface. If the
updraft continues ascending warm moist air in an updraft, the cloud will
continue to grow. This leads to the Mature stage.
In the Mature stage, the raindrops begin to grow
and the cloud begins to expand to great heights. This stage is when the
Cumulonimbus cloud has been built. The droplets within the cloud collide with
other drops and begin to become heavy. Once they become heavy enough, they
descend through the Cumulonimbus cloud. Both the droplets and cool air rushes
to the surface, called a downdraft. During the Mature stage, both
updrafts and downdrafts can occur. If the updraft continues so does the storm.
If the updraft weakens and the downdraft take over, our final stage will
appear, the Dissipating stage.
The Dissipating stage is the ending stage of the
Cumulonimbus cloud. Eventually the downdraft overpowers the updraft by limiting
its supply of warm moist air. It leaves behind the reminisce of what was a
Cumulonimbus clouds.