Cirrus uncinus cloud

Cirrus uncinus
Cirrus uncinus cloud
Abbreviation	Ci unc
Genus	Cirrus (curl of hair)
Species	uncinus (hooked)
Altitude	Above 7000 m (Above 23,000 ft)
Classification	Family A (High-level)
Appearance	curly, hooked
Precipitation cloud?	No, but may indicate precipitation approach.

Cirrus uncinus is a type of cirrus cloud. The name cirrus uncinus is derived from Latin, meaning "curly hooks". Also known as mares' tails, these clouds are generally sparse in the sky and very thin.

The clouds occur at very high altitudes, at a temperature of about −50 to −40 °C (−58 to −40 °F). They are generally seen when a warm or occluded front is approaching. They are very high in the troposphere and generally mean that precipitation, usually rain, is approaching.