Cirrus clouds form high in the troposphere. It is so cold this high in the sky that the clouds are made entirely from ice crystals. Strong winds blow the crystals into whispy strands, sometimes called "mare's tails." You often see cirrus clouds on a clear day–by watching their movement, you can see from which direction the weather is approaching. They are high wispy forms of clouds that don’t form any type of precipitation. Cirrus clouds are formed when water vapor freezes above an altitude of 26,000 feet (8,000 meters). Since there isn’t much moisture in the Earth's atmosphere at that height, the clouds form in thin and delicate shapes. Cirrus clouds may also form after thunderstorms. Typically, Cirrus clouds are a predictor of a change of weather in the near future, except during current times, when the sky is usually in a fair condition.
- Above 23,000 feet
- Water Cycle