Cumulonimbus capillatus

Hazardous cloud

Cumulonimbus capillatus

Abbreviation	Cb cap.
Symbol
Altitude	Ground to 23,000 m (75,000 ft)
Appearance	Dark-based storm cloud capable of impressive vertical growth, with a fibrous upper portion
Precipitation	Very often rain, snow, snow pellets, or hail; heavy at times

A cumulonimbus capillatus is a cumulonimbus cloud with dense cirrus clouds above it, making the cloud top appear to contain hair-like structures. The name comes from the Latin word capillatus, meaning "with hair".^[1]

It is an intermediate stage between cumulonimbus calvus and cumulonimbus incus.

Hazards

A cumulonimbus capillatus is a mature and powerful cumulonimbus cloud and can produce multiple severe weather.

Lightning; this is a strong thunderstorm cloud and it is capable of producing bursts of cloud to ground and cloud to cloud lightning.
Hail; hailstones may fall from this cloud if it is in a highly unstable environment (which favors a more vigorous storm updraft).
Heavy rain; the cloud may drop several inches of rain in a short amount of time. This can cause flash flooding.
Strong wind; gale-force winds from a downburst may occur under this cloud.

References

^ "capillatus". Oxford Reference. Oxford University Press. Retrieved 2021-10-18.

Cloud genera and selected species, supplementary features, and other airborne hydrometeors - WMO Latin terminology except where indicated

Mesospheric

Extreme-level
80–85 km

Noctilucent (NLC) Polar mesospheric clouds	Noctilucent type I veils Noctilucent type II bands Noctilucent type III billows Noctilucent type IV whirls

Stratospheric

Very high-level
15–30 km

Nacreous polar stratospheric clouds (PSC)	Cirriform nacreous Lenticular nacreous
Nitric acid and water polar stratospheric clouds (PSC)	No differentiated sub-types; tends to resemble cirrostratus

Tropospheric

High-level
3–18 km

Cirrus (Ci)

Species	Cirrus castellanus (Ci cas) Cirrus fibratus (Ci fib) Cirrus floccus (Ci flo) Cirrus spissatus (Ci spa) Cirrus uncinus (Ci unc)
Ci-only varieties	Cirrus intortus (Ci in) Cirrus vertebratus (Ci ve)

Cirrocumulus (Cc)

Species	Cirrocumulus castellanus (Cc cas) Cirrocumulus floccus (Cc flo) Cirrocumulus lenticularis (Cc len) Cirrocumulus stratiformis (Cc str)

Cirrostratus (Cs)

Species	Cirrostratus fibratus (Cs fib) Cirrostratus nebulosus (Cs neb)

High-level-only
mutatus cloud

Mutatus non-height specific (see below)

Medium-level
2–8 km

Altocumulus (Ac)

Species	Altocumulus castellanus (Ac cas) Altocumulus floccus (Ac flo) Altocumulus lenticularis (Ac len) Altocumulus stratiformis (Ac str) Altocumulus volutus (Ac vol)

Altostratus (As)

Altostratus undulatus

Nimbostratus (Ns)
Multi-level

Varieties	Nimbostratus virga (Ns vir)

Low-level
0–2 km

Cumulonimbus (Cb)
Towering vertical

Species	Cumulonimbus calvus (Cb cal) Cumulonimbus capillatus (Cb cap)
Cb-only supplementary features	Cumulonimbus cauda ((cau) Tail cloud) Cumulonimbus incus (inc) Cumulonimbus murus ((mur) Wall cloud)
Cb-only accessories and other	Cumulonimbus flumen ((Cb flu) Beaver tail) Overshooting top Hot tower

Cumulus (Cu)
Variable vertical extent

Species	Fractus Cumulus humilis (Cu hum) Cumulus mediocris (Cu med) (Cumulus congestus (Cu con) (Cumulus castellanus (unofficial alternative name for Cu con)) (ICAO term for Cu con and "Cu cas" is Towering cumulus [Tcu]))
Other	Horseshoe Trade wind cumulus

Stratus (St)

Species	Stratus fractus (St fra) Stratus nebulosus (St neb)
St-only genitus cloud and other	Stratus silvagenitus (St sil) Fog (Fg) Surface level

Stratocumulus (Sc)

Species	Stratocumulus castellanus (Sc cas) Stratocumulus floccus (Sc flo) Stratocumulus lenticularis (Sc len) Stratocumulus stratiformis (Sc str) Stratocumulus Undulatus Stratocumulus volutus (Sc vol)

Low-level-only
supplementary features

Arcus ((arc) Shelf)
Tuba ((tub) Funnel cloud)

Low-level-only
accessory cloud and other

Pileus (pil)
Velum (vel)
Pannus (pan)
Other- Actinoform cloud (Stratocumulus)

Non-height
specific

Varieties	Duplicatus (du) Lacunosus (la) Opacus (op) Perlucidus (pe) Radiatus (ra) Translucidus (tr) Undulatus (un)
Supplementary features	Asperitas (asp) Cavum (cav) Fluctus (flu) Mamma (mam) Praecipitatio (pra) Virga (vir)
Mother clouds and human-made clouds	(Mother cloud)+genitus (e.g. cumulogenitus (cugen) (Mother cloud)+mutatus (e.g. cumulomutatus (cumut) Homogenitus (hogen) Homomutatus (homut)