Definition of cumulus clouds

1) Clouds forming in the troposphere which are vertically formed with flat bases and fluffy, rounded tops. They have often been described as cauliflower-like in structure. They occur at heights of 500-6000 meters in elevation from the earth and most often occur scattered or in dense heaped packs. They are formed due to buoyant upward convection during warm, anti-cyclonic summer weather.

source: [Nature; v363; p584-585; 1993.] [Journal of Atmospheric Science; v50; 3894-3908; 1993.] [Journal of Applied Meteorology; v32; 626-641; 1993.]