A cumulonimbus incus (Latin ''incus'', "

anvil An anvil is a metalworking tool consisting of a large block of metal (usually forged or cast steel), with a flattened top surface, upon which another object is struck (or "worked"). Anvils are as massive as practical, because the higher th ...

"), also known as an anvil cloud, is a

cumulonimbus cloud Cumulonimbus (from Latin ''cumulus'', "heaped" and ''nimbus'', "rainstorm") is a dense, towering vertical cloud, typically forming from water vapor condensing in the lower troposphere that builds upward carried by powerful buoyant air currents. ...

which has reached the level of stratospheric stability and has formed the characteristic flat, anvil-top shape. It signifies the

thunderstorm A thunderstorm, also known as an electrical storm or a lightning storm, is a storm characterized by the presence of lightning and its acoustic effect on the Earth's atmosphere, known as thunder. Relatively weak thunderstorms are someti ...

in its mature stage, succeeding the cumulonimbus calvus stage. Cumulonimbus incus is a sub-form of Cumulonimbus capillatus.

Hazards

A cumulonimbus incus is a mature thunderstorm cloud generating many dangerous elements. *

Lightning Lightning is a naturally occurring electrostatic discharge during which two electric charge, electrically charged regions, both in the atmosphere or with one on the land, ground, temporarily neutralize themselves, causing the instantaneous ...

: this storm cloud is capable of producing bursts of cloud-to-ground lightning. *

Hail Hail is a form of solid precipitation. It is distinct from ice pellets (American English "sleet"), though the two are often confused. It consists of balls or irregular lumps of ice, each of which is called a hailstone. Ice pellets generally fal ...

: hailstones may fall from this cloud if it's a highly unstable environment (which favours a more vigorous storm

updraft In meteorology, an updraft is a small-scale current of rising air, often within a cloud. Overview Localized regions of warm or cool air will exhibit vertical movement. A mass of warm air will typically be less dense than the surrounding region, ...

). * Heavy

rain Rain is water droplets that have condensed from atmospheric water vapor and then fall under gravity. Rain is a major component of the water cycle and is responsible for depositing most of the fresh water on the Earth. It provides water f ...

: this cloud may drop several inches (millimetres) of rain in a short amount of time. This can cause

flash flood A flash flood is a rapid flooding of low-lying areas: washes, rivers, dry lakes and depressions. It may be caused by heavy rain associated with a severe thunderstorm, hurricane, or tropical storm, or by meltwater from ice or snow flowing o ...

ing. * Strong

wind Wind is the natural movement of air or other gases relative to a planet's surface. Winds occur on a range of scales, from thunderstorm flows lasting tens of minutes, to local breezes generated by heating of land surfaces and lasting a few hou ...

: gale-force winds from a

downburst In meteorology, a downburst is a strong downward and outward gushing wind system that emanates from a point source above and blows radially, that is, in straight lines in all directions from the area of impact at surface level. Capable of pro ...

may occur under this cloud. *

Tornadoes A tornado is a violently rotating column of air that is in contact with both the surface of the Earth and a cumulonimbus cloud or, in rare cases, the base of a cumulus cloud. It is often referred to as a twister, whirlwind or cyclone, altho ...

: in severe cases (most commonly with

supercell A supercell is a thunderstorm characterized by the presence of a mesocyclone: a deep, persistently rotating updraft. Due to this, these storms are sometimes referred to as rotating thunderstorms. Of the four classifications of thunderstorms (s ...

s), it can produce tornadoes.

Classification

Cumulonimbus clouds can be powerful. If the correct atmospheric conditions are met, they can grow into a

storm. This cloud may be a

single-cell thunderstorm Single cell and similar can mean: Biology * Single-cell organism *Single-cell protein * Single-cell recording, a neuro-electric monitoring technique * Single-cell sequencing **Single cell epigenomics * Single-cell transcriptomics Other * Single-cel ...

or one cell in a

multicellular thunderstorm A multicellular thunderstorm cluster is a thunderstorm that is composed of multiple cells, each being at a different stage in the life cycle of a thunderstorm. It appears as several anvils clustered together. A cell is an updraft/downdraft couple ...

. They are capable of producing severe storm conditions for a short amount of time.

In popular culture

* It is a key plot point in the anime

Tenki no Ko is a 2019 Japanese animated romantic fantasy film produced by CoMix Wave Films and distributed by Toho. It depicts a high school boy who runs away from his rural home to Tokyo and befriends an orphan girl who has the ability to control the we ...

(Weathering With You).

References

External links

Cumulus Cirrus {{Cloud-stub fr:Cumulonimbus#Cumulonimbus capillatus et incus