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.[1]
The clouds occur at 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.[2]
Cirrus uncinus clouds in Salinas Victoria, Nuevo Leon, Mexico.