Altocumulus volutus

{{Short description|Relatively rare type of cloud formation}}

{{Infobox Cloud

|name=Altocumulus volutus

|image location=Altocumulus volutus (22112021).jpg

|image name= Distant altocumulus volutus cloud

|abbreviation=Ac vol

|symbol=

|genus=Altocumulus

|species=Volutus

|variety=

|altitude_m=2,000-7,000

|altitude_ft=7,000-23,000

|level= mid

|appearance=small, single, horizontal, rolling mid-level altocumulus line

|precipitation=None

}}

Altocumulus volutus is a type of altocumulus cloud. This cloud type has the appearance of a single, small, horizontal, rolling line, it is relatively rare compared with its counterpart stratocumulus volutus,{{Cite web|url=https://cloudatlas.wmo.int/clouds-species-volutus.html|title=Volutus|website=International Cloud Atlas}} This cloud does not attach to any other cloud. It may or may not appear with altocumulus clouds of different species. When found in a thunderstorm, it forms when cold air from a thunderstorm's downdraft makes the already present warm and moist air rise, expanding and cooling as it rises. It then condenses, although the most likely scenario is that it condenses into a shelf cloud or roll cloud, rather than an altocumulus volutus cloud.{{cite web|url=https://www.metoffice.gov.uk/weather/learn-about/weather/types-of-weather/clouds/other-clouds/arcus#:~:text=How%20do%20arcus%20clouds%20form,patterns%20associated%20with%20Arcus%20clouds.|title=Arcus cloud|website=Met Office|access-date=2021-11-19}} When found in environments where it is not associated with a thunderstorm, it forms because of wind shear (difference of wind speed and direction between the mid-levels of the atmosphere and the surface).{{Cite web|url=https://skybrary.aero/articles/volutus|title=Volutus|date=July 19, 2021|website=SKYbrary Aviation Safety}}