Cloud Facts

A cloud is water in the atmosphere (air) that we can see. It is where rain and snow comes from. Water on the Earth evaporates (turns into an invisible gas) and rises up into the sky. Higher up where the air is colder, the water condenses: it changes from a gas to drops of water or crystals of ice. We see these drops of water as clouds. See the list below for more facts about clouds.

  • Clouds are made up of tiny water droplets or ice crystals. The droplets and crystals are very light and they can float in the air.
  • Clouds are formed when warm air rises, expands and then cools. This cool air can’t hold as much water vapor as the warm air. The vapor will then begin to condense and form itself around dust particles that are floating in the air. When billions of these particles come together , they form a cloud.
  • Clouds can be grouped into several types: High clouds that form above 18,000 feet are called “Cirrus” clouds. Clouds that form between 6,500 feet to 18,000 feet are called “Alto” clouds. Clouds that form low in the sky , up to 6,500 feet are called “Stratus” clouds. Clouds that grow vertically are called “Cumulus” clouds. Special clouds are called: Mammatus, Lenticular, Contrails ,and Fog.
  • There are three types of Cirrus clouds: Cirrus, Cirrostratus and Cirrocumulus. There are two types of Alto clouds: Altostratus and Altocumulus. There are three types of Stratus clouds: Stratus, Stratocumulus and Nimbostratus.
  • Cumulonimbus clouds are thunderstorm clouds.
  • The thin wispy clouds that can be seen in the sky are the Cirrus clouds.
  • If you see a green cloud it is highly likely that a severe thunderstorm with hail and/or tornadoes is approaching.
  • Moisture condenses into fog when air is cooled from below.
  • Clouds that are white are actually reflecting light from the sun.
  • Clouds move when they are pushed by the wind. The high Cirrus clouds can move as fast as 100 miles per hour. Thunderstorm clouds (Cumulonimbus) usually travel around 40 miles per hour.