Appendix G - Clouds: Foretellers of Weather

About 200 years ago an Englishman classified clouds
according to what they looked like to a person seeing them
from the ground. He grouped them into three classes and
gave them Latin names: cirrus, cumulus, and stratus.
These three names, alone and combined with other Latin
words, are still used to identify different cloud formations.
By being familiar with the different cloud formation and
what weather they portend, you can take appropriate action
for your protection.

Cirrus clouds are the very high clouds that look like thin streaks or curls.
They are usually 6 kilometers or more above the earth and are usually a sign
of fair weather. In cold climates, however, cirrus clouds that begin to
multiply and are accompanied by increasing winds blowing steadily from a
northerly direction indicate an oncoming blizzard.

Cumulus clouds are fluffy, white, heaped-up clouds. These clouds, which are
much lower than cirrus clouds, are often fair weather clouds. They are apt to
appear around midday on a sunny day, looking like large cotton balls with flat
bottoms. As the day advances, they may become bigger and push higher
into the atmosphere. Piling up to appear like a mountain of clouds. These can
turn into storm clouds.

Stratus clouds are very low, gray clouds, often making an even gray layer
over the whole sky. These clouds generally mean rain.

Nimbus clouds are ram clouds of uniform grayness that extend over the
entire sky

Cumulonimbus is the cloud formation resulting from a cumulus cloud
building up, extending to great heights, and forming in the shape of
an anvil. You can expect a thunderstorm if this cloud is moving in your
direction.

Cirrostratus is a fairly uniform layer of high stratus clouds that are
darker than cirrus clouds. Cirrostratus clouds indicate good weather.

Cirrocumulus is a small, white, round cloud at a high altitude. Cirrocumulus
clouds indicate good weather.

A loose, vapory cloud (scud) driven before the wind is a sign of
continuing bad weather.