Here's why:
* Altitude: Cirrus clouds form at altitudes above 6,000 meters (20,000 feet). They're the highest of all the major cloud types.
* Composition: They are made up of ice crystals, as the temperature at those heights is well below freezing.
* Appearance: Cirrus clouds appear wispy, feathery, and often look like delicate strands of hair or feathers. They are often called "mare's tails" because of their appearance.
Other types of high-altitude clouds include:
* Cirrocumulus: These look like small, white patches or ripples of cotton. They are often called "mackerel sky" because of their resemblance to fish scales.
* Cirrostratus: These are thin, sheet-like clouds that cover the sky. They can cause halos around the sun or moon.
While these clouds are high in the atmosphere, they can be a sign of approaching weather changes. For example, cirrus clouds can indicate the arrival of a warm front.
