clouds
How do they form?• Clouds form as warm air is forced
upward, expands, and cools.
• When warm, moist air cools, the water vapor turns into liquid
droplets or freezes into ice crystals depending on the temperature.
• These droplets and crystals come together to form…clouds!
How are they classified?• By SHAPE and HEIGHT
• The shape and height of clouds depends on: temperature,
pressure, and the amount of water vapor in the atmosphere.
• By the way…how many layers of the atmosphere are there?
What shapes do clouds come in?3 main cloud shapes:
• STRATUS form layers, or smooth even sheets in the sky
• CUMULUS puffy, white clouds with flat bottoms
• CIRRUS curly, wispy, and look like they are made of thin fibers
Stratus clouds…•Form layers, or smooth even
sheets in the sky
• Usually at low altitudes below 2,ooom
• Often cover large areas & block out sun, Can mean continuous heavy rain or steady drizzle.
•Fog is a type of stratus cloud that is very low to the ground
• Strato- is a prefix that describes low altitude clouds
cumulus clouds…•White, puffy clouds, with
flat bottoms
•Form when warm air rises
• Usually at mid-altitudes (2000-6000m), but
sometimes tower to great heights
• Usually means fair weather or thunderstorms
(cumulonimbus clouds)
• Curly, wispy, and look like they are made of thin fibers
•Form when the wind is strong, usually indicate a possible change in
weather.
• Usually at high altitudes (6,000-8,000m)
• Usually mean fair weather, but can indicate approaching storms
• Made of ice crystals
• Cirro- is a prefix that describes high altitude clouds
cirrus clouds…
Cloud prefixes…
Clouds are also classified by their height:
• Cirro- = high clouds
• Alto- = mid-elevation clouds
• Strato- = low clouds
• EXAMPLE: cirrostratus clouds are high clouds that look like flat
sheets or layers in the sky
Last, but not least…Some clouds are known as “rain
clouds”:
• Clouds associated with precipitation often have the word NIMBUS attached to
them.
• Nimbus is Latin for “dark rain cloud”
•Nimbus clouds are generally found at very low altitudes
•EXAMPLE: When a cumulus cloud grows into a thunderstorm, it is called a
cumulonimbus cloud. Nimbostratus clouds are layered rain clouds.