page_title: List of cloud types
section_title: Genus cumulonimbus: Towering vertical
hierarchical_section_title: List of cloud types / Cloud identification and classification in the troposphere / Towering vertical cumulonimbiform and cumuliform (low to mid-level cloud base) / Genus cumulonimbus: Towering vertical
caption_attribution_description: English: Cumulonimbus incus @ mykonos / Greece - 6/2009
context_page_description: The list of cloud types groups the main genera as high, middle, multi-level, and low according to the altitude level or levels at which each cloud is normally found. Small cumulus are commonly grouped with the low clouds because they do not show significant vertical extent. Of the multi-level genus-types, those with the greatest convective activity are often grouped separately as towering vertical. The genus types all have Latin names.
  The genera are also grouped into five physical forms. These are, in approximate ascending order of instability or convective activity: stratiform sheets; cirriform wisps and patches; stratocumuliform patches, rolls, and ripples; cumuliform heaps, and cumulonimbiform towers that often have complex structures. Most genera are divided into species with Latin names, some of which are common to more than one genus. Most genera and species can be subdivided into varieties, also with Latin names, some of which are common to more than one genus or species.
context_section_description: Abbreviation: Cb
  Clouds of the genus cumulonimbus have very dark gray to nearly black flat bases and very high tops that can penetrate the tropopause. They develop from cumulus when the airmass is convectively highly unstable. They generally produce thunderstorms, rain or showers, and sometimes hail, strong outflow winds, and/or tornadoes at ground level.
  Species
  Cumulonimbus calvus (V-57)
  Cumulonimbus with high domed top.
  Cumulonimbus capillatus (V-58)
  Towering vertical cloud with high cirriform top.
  Varieties
  No varieties (always opaque and does not form in patterns visible from surface level).
  Precipitation-based supplementary features
  Associated with calvus and capillatus species.
  Virga
  Precipitation that evaporates before reaching the ground.
  Praecipitatio
  Precipitation that reaches the ground.
  Cloud-based supplementary features
  Incus (species capillatus only)
  Cumulonimbus with flat anvil-like cirriform top caused by wind shear where the rising air currents hit the inversion layer at the tropopause.
  Mamma
  Also sometimes called Mammatus, consisting of bubble-like protrusions on the underside caused by localized downdrafts.
  Arcus (including roll and shelf clouds)
  Low, horizontal cloud formation associated with the leading edge of thunderstorm outflow.
  Tuba
  Column hanging from the cloud base which can develop into a funnel cloud or tornado.
  Accessory clouds
  Seen with species and capillatus except where noted.
  Pannus
  Accompanied by a lower layer of fractus species cloud forming in precipitation.
  Pileus (species calvus only)
  Small cap-like cloud over parent cumulonimbus.
  Velum
  A thin horizontal sheet that forms around the middle of a cumulonimbus.
  Genitus mother clouds
  Cumulonimbus altocumulogenitus
  Cumulonimbus altostratogenitus
  Cumulonimbus nimbostratogenitus
  Cumulonimbus stratocumulogenitus
  Cumulonimbus flammagenitus that are formed by large scale fires or volcanic eruptions.
  Mutatus mother cloud
  Cumulonimbus cumulomutatus
caption: Single-cell Cumulonimbus capillatus (V-58) incus
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