Cirrus uncinus cloud

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Cirrus uncinus

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Altitude	Above 7000 m (23,000 ft)
Appearance	curly
Precipitation Cloud?	No
Abbreviation	Ci

Cirrus uncinus is a type of cirrus cloud. Its name 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 minus 40-50 degrees Celsius. 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.

v • d • e Clouds
High Clouds (Family A):	Cirrus (Ci) • Cirrus uncinus • Cirrus Kelvin-Helmholtz colombia • Cirrostratus (Cs) • Cirrocumulus (Cc) • Pileus • Contrail
Middle Clouds (Family B):	Altostratus (As) • Altostratus undulatus • Altocumulus (Ac) • Altocumulus undulatus • Altocumulus mackerel sky • Altocumulus castellanus cloud • Altocumulus lenticularis
Low Clouds (Family C):	Stratus (St) • Nimbostratus (Ns) • Cumulus humilis (Cu) • Cumulus mediocris (Cu) • Stratocumulus (Sc)
Vertical Clouds (Family D):	Cumulonimbus (Cb) • Cumulonimbus incus • Cumulonimbus calvus • Cumulonimbus with mammatus • Cumulus congestus • Pyrocumulus  • Pyrocumulonimbus