Cirrus clouds (cirrus means tuft of hair in Latin) are found above 20,000ft. They occur in fair weather, and they usually point in the direction of the acting winds. They appear as silky, delicate, or tuft of hair (such as a horsetail). They form from tiny ice crystals. One common feature is the fall streaks it has, that result from falling ice crystals, or blown away ice crystals by high winds. The streaks may look like fine lines, comma-shaped, or a mix of irregular lines, but generally move across the sky from west to east.

Did you know:

Cirrus clouds are high altitude clouds. Because it is cold up there, water exists in the form of ice particles, which reflect the sunlight and gives it a pure white color. It is very unusual to see dark clouds at very high altitudes.

Other cirrus clouds include the cirrostratus and cirrocumulus.

Cirrostratus:

Like its mother (cirrus), they appear as flattened white sheets spreading across the sky. They are also visible as ripples in the sky. They are clear enough to see the sun or moon through them. Halos are common with cirrostratus clouds, and they often disappear when the ice patches become more and begin to form bigger clouds. During sunset and sunrise, they can look beautiful, reflecting the warm colors of the sun.

Cirrocumulus:

They appear as fine white cotton-balls of clouds that can stretch across the entire skyline. Note that these are not as smooth as the cirrus and cirrostratus but are broken up into smaller elements and ripples. They can look like the scales on the skin of a fish. This is why people call it mackerel sky. They are less common and appear more in colder seasons.