List of cloud types
The list of cloud types groups the tropospheric types as "high" (cirrus, cirrocumulus, cirrostratus), "middle" (altocumulus, altostratus), "multi-level" (nimbostratus, cumulus, cumulonimbus), and "low" (stratocumulus, stratus) according to the altitude level or levels at which each cloud is normally found. Small cumulus are commonly grouped with the low clouds because they do not show significant vertical extent. Of the multi-level genus-types, those with the greatest convective activity are often grouped separately as "towering vertical". The genus types all have Latin names.
Cloud physics
Cumuliform and cumulonimbiform heaps and deep stratiform layers often occupy at least two tropospheric levels, and the largest or deepest of these can occupy all three levels. They may be classified as low or mid-level, but are also commonly classified or characterized as vertical or multi-level. Nimbostratus clouds are stratiform layers with sufficient vertical extent to produce significant precipitation. Towering cumulus (species congestus), and cumulonimbus may form anywhere from near the surface to intermediate heights of around 3 kilometres. Of the vertically developed clouds, the cumulonimbus type is the tallest and can virtually span the entire troposphere from a few hundred metres above the ground up to the tropopause. It is the cloud responsible for thunderstorms.