What Are Nimbus Clouds?

Nimbus Clouds

• The word nimbus comes from a Latin word meaning "rainstorm." Nimbus clouds are so named because they are present in the sky when it rains, or during another type of precipitation such as hail or snow. Nimbus clouds tend to look dark, as they carry a lot of water droplets. They can appear at any level of the troposphere --- low, mid-level or high.

Naming of Clouds

• Clouds are classified using a system based on their appearance from the ground. Latin words are used to describe the appearance. As well as nimbus there are "cumulus," which translates as "heap"; "stratus," which translates as "layer"; and "cirrus," which translates as "curl of hair." These descriptions are then added to words that describe the height of the cloud. For example, "alto" describes clouds at mid-level height, whereas any clouds prefixed by "cirr" are found at high levels. Two common examples of nimbus cloud is "nimbostratus" and "cumulonimbus."

Nimbostratus Clouds

• Nimbostratus clouds are dark gray and are associated with continuously falling rain or snow. The stratus part of their name means layer, and indicates that the clouds form in large sheets with no clear delineations. They appear low in the sky. Like other low cloud types, they are mainly composed of water droplets, as opposed to the ice particles found in higher-level clouds.

Cumulonimbus Clouds

• The "cumulo" part of cumulonimbus refers to the fact that the cloud is large and can have a lot of vertical development, resulting in a heap-like appearance. Cumulonimbus clouds indicate a sudden change in weather and are the type of cloud that you see during thunderstorms. They often occur in large numbers, and are very dark in appearance.