Clouds are categorized by a precise system of classification. Most clouds have Latin names in the form of either prefixes or suffixes. The Latin names were given with regards to their appearance when observed by a person standing on the ground. The universally-acceptable classification of clouds recognizes three basic types that have been listed based upon their elevation from the ground surface:
- High-level Clouds
- Mid-level Clouds
- Low-level Clouds
Cirrus Clouds (High-level clouds)
The Latin word ‘cirrus’ means ‘a tuft of hair’. These clouds are called ‘cirrus’ because they have a feather-like appearance. The presence of dense cirrus clouds is usually linked with a looming disturbance in the weather.
Occurrence: Cirrus clouds are found at very high altitudes of nearly 8000 meters. Usually, they exist in the form of exhaustive stretches, and it is hard to distinguish one cirrus cloud from the other. Due to the extremely high altitudes at which cirrus clouds are formed, they consist of ice crystals. The high elevation also ensures that the amount of moisture is very limited, and this is the principal reason for their thin, hair-like shape.
Cirrus Aviaticus (Contrail): A famous variation of the cirrus is in the form of a contrail or condensation trails. To be precise, a contrail isn’t a true cloud formation. It is a long stream of frozen vapor that can be seen in the sky when emissions from aircraft start freezing in the upper atmosphere.
Cumulus Clouds (Mid-level Clouds)
The word ‘cumulus’ means ‘a heap’. Cumulus clouds have very clearly distinguishable edges and are often described as having a ‘puffy’ or piled-up formation. These clouds tend to stack-up closely and are commonly shaped like big cotton balls. A typical feature of cumulus clouds is the presence of a densely-shaded portion. This is regarded as a defining trait and is used to differentiate them from the other clouds found at higher altitudes.
Occurrence: Cumulus clouds tend to form at varying heights, and their formation is governed by the amount of moisture that is present in the surrounding air. Their formation is also dictated by the convection of heat in the surrounding air.
- Moisture-rich or humid conditions lead to the formation of cumulus clouds at slightly lower levels, usually somewhere near the 2,400 meter altitude mark (a rare incidence).
- In drier conditions, they are formed at much higher altitudes of about 6,000 meters (normal prevalence).
Altocumulus: The most commonly-found form of cumulus clouds are the altocumulus clouds. Their occurrence is looked upon as a warning sign for approaching thunderstorms.
Stratus Clouds (Low-level Clouds)
The Latin word ‘stratus’ means ‘well spread’. These are the clouds that are often seen shrouding the hilltops or peaks of steep cliffs. They usually form in the normal (stable) air itself and are totally turbulence free.
Occurrence: Stratus clouds have a very low base height, and they are sometimes found at 600 meters. When they are found so low, they are referred to as stratus nebulosus. It is a common notion that stratus clouds found near the hills signify rain, though this does not always hold true. Stratus clouds sometimes begin forming at night. However, when the morning sun strikes, they scatter away, leaving behind just tiny droplets as a mark of their overnight existence.
Stratocumulus: these are the most common type of stratus clouds and are marked by shades of grey and white. They are formed in big lumps and are generally found at about 1500 meters.