... vertically developed cumulus with a low dark base and fluffy masses that extend to great... Cumulonimbus - definition of cumulonimbus by The Free Dictionary.

Cumulus Stage. As nouns the difference between cumulonimbus and cumulus is that cumulonimbus is a cloud, with a tall structure and a flat base, that is often associated with thunderstorms while cumulus is a large white puffy cloud that develops through convection on a hot, humid day, they can form towers and even become cumulonimbus clouds. They are formed when warm, moist air rises within the cooler air. Certain Cumulonimbus clouds appear nearly identical with Cumulus congestus. cumulonimbus synonyms, cumulonimbus pronunciation, cumulonimbus translation, English dictionary definition of cumulonimbus. Define cumulonimbus.

The character of the precipitation may help to distinguish Cumulonimbus from Nimbostratus.

Cumulonimbus clouds have 3 distinct 'species' which describe the appearance of the head of the cloud: Cumulonimbus calvus - the top of the cumulonimbus is puffy, like a cumulus cloud. Cumulus cloud is the base of formation of a cumulonimbus cloud and also of tornadoes. The moisture rapidly cools down and condenses to form tiny drops of water, forming the rising cumulus clouds.

Cumulonimbus definition, a cloud of a class indicative of thunderstorm conditions, characterized by large, dense towers that often reach altitudes of 30,000 feet (9000 meters) or more, cumuliform except for their tops, which appear fibrous because of the presence of ice crystals: occurs as a single cloud or as a group with merged bases and separate tops. The water droplets at the top of the cloud tower have not frozen to become ice crystals.

If the precipitation is of the showery type, or if it is accompanied by lightning, thunder or hail, the cloud is Cumulonimbus.