|Occurrence||Worldwide except Antarctica|
|Formation||powerful convection assisted by atmospheric instability|
|Precipitation||Heavy rain or hail|
|Potential Hazards||Severe turbulence, thunderstorms, hail, tornadoes, lightning, strong winds|
Cumulonimbus capillatus is a species of very large cumulonimbus cloud with a developed cirriform top composed of ice crystals (often an anvil, in which case the cloud is a cumulonimbus incus) that can extend to the tropopause. From ground level, cumulonimbus capillatus clouds may look dark grey and cover the sky.