Cirrus vertebratus
Ci ve
Cirrus vertebratus
© wetterkurs.ch
Description
The name "vertebratus" (Latin: vertebrate, furnished with vertebrae) describes the characteristic arrangement of this cirrus cloud, which resembles a spine or a herringbone pattern. The cloud consists of a central band of ice crystals from which fibrous branches extend sideways, similar to the ribs of a skeleton. Cirrus vertebratus forms in the upper troposphere and consists exclusively of ice crystals. This distinctive structure is created by wind shear at various altitudes, with the lateral filaments being drawn apart by differing wind speeds and directions. The vertebratus variety is comparatively rare and ranks among the most visually striking forms of cirrus clouds.
Identification Features
- Central, elongated cloud band from which fibrous branches extend sideways
- Overall structure resembles a spine or herringbone pattern
- Very high in the sky, typically at altitudes above 6,000 metres
- Composed of fine, white ice crystals with a silky sheen
- The lateral filaments are often slightly curved or wavy
- The individual "ribs" are usually arranged on one side or symmetrically on both sides
- Noticeably more structured than ordinary cirrus fibres
- Can occasionally be confused with contrails, but displays a more natural asymmetry
Occurrence by genus
Highlighted: all genera with which vertebratus occurs.
Meteorological Significance
Cirrus vertebratus indicates pronounced wind shear in the upper troposphere, where wind speed or wind direction changes significantly with altitude. The appearance of this cloud form can signal the approach of a jet stream or a frontal zone. As an isolated occurrence, cirrus vertebratus is not yet a reliable indicator of an impending deterioration in weather; however, in combination with increasing cirrus cloud cover, it can herald an approaching warm front. The strong shear can also point to turbulence at high altitudes, which is of relevance to aviation.
Facts
- WMO-Code
- Ci ve
- Height layer
- High clouds
- Typical height
- 6.0 - 12.0 km
- Genus
- CIRRUS