Cumulus congestus cloud (No official abbreviation) is a free convective cloud associated with volcanic eruptions and large-scale fires. Pyrocumulus isn't recognized by the WMO as a distinct genus or species, but is, in essence, cumulus congestus formed under special circumstances that can also cause severe turbulence. Cumulus congestus will mature into cumulonimbus calvus under conditions of sufficient instability. This transformation can be seen by the presence of smooth, fibrous, or striated aspects assumed by the cloud's upper part. This cloud type produces precipitation, often in abundance. These clouds also produce fair weather waterspouts. An approaching weather front often brings mid level clouds such
Cumulus humilis cloud Cumulus humilis cloud Cumulus humilis are cumuliform clouds with little vertical extent, common in the summer, that are often referred to as "fair weather cumulus". If they develop into cumulus mediocris or cumulus congestus, thunderstorms could form later in the day. They generally form at lower altitudes (500–3000 m (1,500–10,000 ft)), but in hot countries or over mountainous terrain these clouds can occur at an altitude of up to . They show no significant vertical development, indicating that the temperature in the atmosphere above them either drops off very slowly or not at all with altitude; that is, the adiabatic