Clouds come in 3 basic shapes
Cirrus (wispy)
Thin, white feathery or wispy clouds, usually separated or detached. Highest of all clouds in tropopause,
they form at 30,000ft (9144m) or more in the sky. They are composed primarily of ice crystals.
Cumulus (heaped & puffy)
Flat-based, billowing clouds with vertical doming. Often the top of cumulus clouds have a "cauliflower-like"
appearance. Cumulus clouds are most prominent during the summer months.
Stratus (layered)
Thin, layered clouds, often occurring as continuous or rippled sheets which cover large portions of the sky.
Stratus clouds are frequently gray and thick.
Cloud altitude ranges
High clouds (between 5500m and 14000m)
comprise of ice crystals:
Cirrus - white filaments
Cirrocumulus - small rippled elements
Cirrostratus - transparent sheet, often with halo
Medium clouds (between 2000m and 7000m)
comprise of water droplets or a mixture of ice crystals & water droplets:
Altocumulus - generally white, layered, rippled elements
Altostratus - grey thin layer
Nimbostratus - thick layer, dark with possibility of rain or snow
Low clouds (below 2000m)
comprise of water droplets:
Stratocumulus - layered series of rounded rolls, generally white
Stratus - layered uniform grey
Cumulus - 'white cauliflower' clouds with flat base
Cumulonimbus - large dark towers, often with 'anvil' tops, associated with heavy rain & thunderstorms
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What are clouds ?
Clouds are made of tiny water droplets, ice crystals or both. Storms and clouds are concentrated in the lower
seven miles or so of the atmosphere known as the troposphere. Clouds can serve as excellent indicators of
changing weather. In general, flat clouds indicate stable conditions while piled-up clouds mean unstable air.
How do clouds form ?
Clouds are formed by the gathering of condensing water vapor. Moist air near the Earth’s surface raises up
from the ground into the atmosphere by either the sun's heat or by a colder invading air mass (called a cold front),
that pushes the warm moist air upward. This lifting of the air drops both the air pressure and temperature.
Then when the air temperature reaches the air’s dew point, the water vapor air condenses, and forms into clouds.
The darker clouds we can see when a storm is brewing, are thicker clouds filled with lots of water molecule's,
which restrict the amount of sunlight that can pass through makings the clouds appear dark.
What is rain ?
To get rain, the condensing water vapor in the clouds need to become heavy enough to fall out of suspension.
In the begining the tiny droplets aren't heavy enough to fall, so just hang there suspended in the air.
To become heavier, the droplets need to grow into drops. This happens by them acquiring more water and become larger. Some will collide with other droplets and become larger, or will grow as water condenses out the air directly into the droplet.
After time the droplets will reach a size/mass when they won't be able to stay floating in the cloud because they are too heavy and therefore will start to fall. Some may get blown back up into the clouds until they are heavy enough to overcome the force of the wind. Then they will fall to earth as rain and will continue to keep falling as long as the conditions are right to make the clouds and let the water droplets grow heavy enough to fall.
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