Cumulonimbus (Cb) is a type of cloud that is tall, dense, and involved in thunderstorms and other intense weather. It is a result of atmospheric instability. These clouds can form alone, in clusters, or along a cold front in a squall line.

They create lightning through the heart of the cloud. Cumulonimbus clouds form from cumulus clouds (namely from cumulus congestus) and can further develop into a supercell, a severe thunderstorm with special features. Cumulonimbus clouds usually form from cumulus clouds at a much lower height, thus making them, like cumulus clouds, grow vertically instead of horizontally, thus giving the cumulonimbus its mushroom shape.

The base of a cumulonimbus can be several miles across, and it can be tall enough to occupy middle as well as low altitudes; though formed at an altitude of about 500 to 13,000 feet), its peak can reach up to 23,000 meters (75,000 feet)[citation needed] in extreme cases. Typically, it peaks at a much lower height (usually up to 20,000 feet).[verification needed]. Well-developed cumulonimbus clouds are also characterized by a flat, anvil-like top (anvil dome), caused by straight line winds at the higher altitudes which shear off the top of the cloud, as well as by an inversion over the thunderstorm caused by rising temperatures above the tropopause.

This anvil shape can precede the main cloud structure for many miles, causing anvil lightning. This is the tallest of the clouds. Cumulonimbus storm cells can produce heavy rain (particularly of a convective nature) and flash flooding, as well as straight-line winds.

Most storm cells die after about 20 minutes, when the precipitation causes more downdraft than updraft, causing the energy to dissipate. If there is enough solar energy in the atmosphere, however (on a hot summer's day, for example), the moisture from one storm cell can evaporate rapidly—resulting in a new cell forming just a few miles from the former one. This can cause thunderstorms to last for several hours.

This multicell cloud structure exists until a cold downdraft preceding the cumulonimbus at ground level flows before the cloud at a distance sufficient to disrupt updraft (5–10 kilometers). From this moment on the cumulonimbus cloud quickly degrades and dissipates, forming cirrus spissatus, dense anvil-like cirrus, stratocumulus diurnalis or stratocumulus vesperalis.

Similar to 0 things you like: