CLOUDS

clouds What are clouds made of? Clouds are made up of lots of tiny water droplets or ice particles floating in the sky at different heights. How do clouds form? As the sun heats water it turns into an invisible gas called water vapour, this is called evaporation. The higher up you get in the sky, the cooler the temperature, so as water vapour rises it cools. Eventually it becomes cool enough to turn back into water and a cloud forms, which we can see in the sky.

Water evaporates from oceans and land surfaces. Water vapor rises into the atmosphere and begins to cool. As the water cools it begins to condense into small water droplets or ice crystals. Water droplets and ice crystals form clouds. Once the clouds have enough water, rain or snow begins to fall. Precipitation then collects on the surface and begins the Water Cycle again.

Main Types of root clouds names Stratus Cirrus Cumulus Nimbus However, these names change based on the formation!

NAMES FOR CLOUDS Most of our names for clouds come from Latin and are usually a combination of the following prefixes and suffixes: Stratus/strato = flat/layered and smooth Cumulus/cumulo = heaped up/puffy, like cauliflower Cirrus/cirro = High up/wispy Alto = Medium level Nimbus/Nimbo = Rain-bearing cloud Where these names are combined we can often build up an idea of that cloud's character. For example, if we combine nimbus and stratus we get 'nimbostratus' - a cloud which is flat and layered and has the potential for rain.

Height level clouds High clouds (CH) Base usually 20,000 ft or above Cirrus Cirrocumulus Cirrostratus Medium clouds (CM) Base usually between 6,500 and 20,000 ft Altocumulus Altostratus Nimbostratus Low clouds (CL) Base usually below 6,500 ft Stratocumulus Stratus Cumulus Cumulonimbus

Cumulus These look like fluffy balls of cotton wool. Usually cumulus are found on calm clear days and indicate fair weather, but they can grow into towering thunderstorms given the right conditions.

Stratus These are flat, grey, featureless layers which often sit low to the ground, hiding the clouds above. Sometimes these can produce a light drizzle. Fog is simply a stratus cloud which has come down to surface level, so when you walk through fog, you are actually walking through a cloud.

Cirrus Cirrus are the highest level clouds, made entirely of ice, this are wispy looking clouds which look like horses tails.

Nimbostratus 'Nimbus' is the Latin for rain cloud. Nimbostratus produces long lasting rain or snow that is light to moderate intensity. These are tall stratus clouds existing at low and mid levels.

Cumulonimbus Also known as 'the king of clouds' cumulonimbus are responsible for bringing very heavy rain and hail to an area over a short space of time. These are also the only clouds that can produce thunder and lightning. Cumulonimbus are very tall and grow through all layers of the sky often with a giant 'anvil' shaped top.

Stratocumulus A layer of stratus clouds can break up to form cumulus or an area of cumulus can squeeze together to form stratus. The period in between is its own type of cloud, known as stratocumulus.

How do thunderstorms form? Thunderstorms start out as small cumulus clouds. As more moisture enters the atmosphere, the cumulus clouds begin to build into larger and higher clouds forming cumulonimbus clouds. As more and more rain falls from the cumulonimbus clouds, the cloud gets smaller and eventually it stops raining.

Review

Guess the cloud type Cirrus

1) This is a large cumulonimbus cloud building into a severe thunderstorm.

Fog

Cumulus

Stratus

Nimbostratus

Cirrus and cumulus

Stratus and fog

Trick! This is smoke