Cirrus cloud - Definition

For the aircraft manufacturer, see Cirrus Design.

Wispy Cirrus clouds centre of image

Cirrus (Lat. 'wisp of hair') is a type of cloud.

Cirrus clouds are composed of ice crystals and shaped like hairlike filaments. They are formed at an altitudes above 16,500 feet. If there are many cirrus clouds in the sky it may be a sign that a frontal system is approaching. Cirrus clouds can also be the remnants from a thunderstorm.

See also

weather, atmosphere

External link

• Photograph of cirrus clouds illuminated by sunset (http://wetterchronik.de/mm/sonne/20040426u.htm)
• cirrus clouds on the planet Mars (http://marsrovers.jpl.nasa.gov/gallery/press/opportunity/20041213a/merb_sol290_clouds-B313R1_br.jpg)