Categories of Clouds

The scientific study of clouds began in 1803 when Luke Howard, a British pharmacist and amateur meteorologist, introduced the first system for classifying clouds. Although many other procedures for cloud classification have been devised over the years, Howard’s system is so simple and effective that it is still in use today. It is based on the shape, distribution, and altitude of clouds. He identified ten different categories, but they are all variations of three basic cloud forms. Clouds can be divided into three groups: cirrus (meaning “curl”), stratus (“spreading out in layers or sheets”), and cumulus (“a pile or heap”).

The first kind of cloud is the cirrus cloud. It is sometimes called “mares’ tails” because it tends to look like the tail of a horse. Cirrus clouds move at speeds of 100 to 200 miles per hour, but their height makes their speed seem much slower. They are the highest of all clouds and are found about five miles above sea level. Cirrus clouds look white, curly, feathery, delicate, streaky, wispy, and thin because of their shape, distribution, and height.

The second type of cloud is the stratus cloud. These clouds look like a gray sheet or blanket, but they are not very thick, so blue sky often shines through. They are usually arranged in smooth, flat layers. They are found one to four miles above Earth. Because of their height and shape, they are sometimes called “mackerel sky”.

The third category