Cumulonimbus, from the
Latin cumulus ("heap") and nimbus ("rainstorm", "storm cloud"), is a dense towering vertical
cloud associated with
thunderstorms and
atmospheric instability, forming from water vapor carried by powerful upward air currents. Cumulonimbus can form alone, in clusters, or along
cold front squall lines. These clouds are capable of producing
lightning and other dangerous severe weather, such as
tornadoes. Cumulonimbus progress from overdeveloped
cumulus congestus clouds and may further develop as part of a
supercell. Cumulonimbus is abbreviated
Cb and are designated in the D2 family.