Low-level Clouds - Cumulonimbus (Cb) with anvil
Notes: The characteristic shape of these clouds can only be seen as a whole when viewed from a distance. The tops of these massive clouds show a fibrous or striated structure that frequently resembles an anvil, plume or huge mass of hair. They may occur as an isolated cloud or an extensive wall and squalls, hail and/or thunder often accompany them.
Underneath the base, which is often very dark, Stratus fractus (L7) frequently form and, in storms, these may be only a few hundred feet above the earth's surface and they can merge to form a continuous layer.
Mamma may form, especially on the underside of the projecting anvil and may appear particularly prominent when the sun is low in the sky. A whole variety of other clouds such as dense cirrus, altocumulus, altostratus, stratocumulus, cumulus and stratus may also be present.
