Deep Blue Sky With Various White Clouds 7 Royalty-Free Stock Photography

The list of cloud types groups all cloud genera as high (cirro-, cirrus), middle (alto-), multi-level (nimbo-, cumulo-, cumulus), and low (strato-, stratus). These groupings are determined by the altitude level or levels in the troposphere at which each of the various cloud types is normally found. Small cumulus are commonly grouped with the low clouds because they do not show significant vertical extent. The genera are also grouped into five physical forms. These are, in approximate ascending order of instability or convective activity: stratiform sheets cirriform wisps and patches stratocumuliform patches, rolls, and ripples cumuliform heaps, and cumulonimbiform towers that often have complex structures.