Arcus (cloud)

Clouds : classification
Genera Cirrus Ci Cirrocumulus Cc Cirrostratus Cs Altocumulus Ac Altostratus As Stratocumulus Sc Stratus St. Cumulus Cu Nimbostratus Ns Cumulonimbus Cb	species calvus cal capillatus cap castellanus cas congestus con fibratus fib floccus flo fractus fra humilis hum lenticularis len mediocris med nebulosus neb spissatus spi stratiformis st uncinus unc volutus vol	Subspecies duplicatus you intortus in lacunosus la opacus op perlucidus pe radiatus ra translucidus tr undulatus un vertebratus ve Special forms arcus arc asperitas asp cauda cau cavum cav fluctus flu flumen flm incus inc mamma mam murus mur pannus pan pileus pil praecipitatio pra tuba tub velum vel virga vir

Arcus ( Latin: "bow", abbreviation arc ) is a low, dense, horizontal formation with more or less tattered edges, which occurs on the lower part of the front of certain clouds. At a greater extent it has the appearance of a dark, threatening arc. This special form occurs with Cumulonimbus and - less frequently - also with Cumulus . It is usually associated with strong gusts , which is why it is also called a gust roller or gust collar.

Web links

Commons : Arcus  - collection of images, videos and audio files

Karlsruhe Cloud Atlas:

• Cumulonimbus arcus
• Cumulonimbus capillatus praecipitatio arcus
• Cumulus congestus arcus