Luke Howard noticed that clouds often have features of two or more categories, such as cirrus + stratus, cumulus + stratus, etc. Based on these observations, he suggested modifications (or combinations) of the core four clouds  between  categories. This research served as the starting point for the ten basic types of clouds we observe. From the World Meteorological Organization's (WMO)  International Cloud Atlas , the official worldwide standard for clouds, the following are definitions of the ten basic cloud types, divided by their height: High-Level Clouds Cirrus  (Ci), c irrocumulus  (Cc), and  cirrostratus  (Cs) are high level clouds. They are typically thin and white in appearance, but can appear in a magnificent array of colors when the sun is low on the horizon. Cirrus (Ci) Detached clouds in the form of white, delicate filaments, mostly in patches or narrow bands. They may have a fibrous (hair-like) and/or silky sheen appearance.…