Before learning about the types of clouds, lets first understand what are clouds??
What are clouds ?
Clouds may be defined as agglomerate of several tiny water droplets, ice particles or mixture of both in the air, generally above the ground surface.
How are they formed ?
When air rises, it gets cooled due to expansion. Once dew point is reached, the cooling of air leads to condensation of water vapors in the atmosphere, These water vapors which are too small (Less than 0.001 cm in radius )to fall as rain or snow remain suspended in the form of clouds .Each cloud particle gets formed around a solid matter, called as condensation nuclei. Dust particles, salt particles suspended in air(from sea water) act as an excellent source of condensation nuclei.
What are the types of clouds ?
Clouds have been classified by taking into account a number of characteristics such as height, form, appearance etc. This classification can be seen by the following diagram :
1- High Clouds– They form at about 6- 12 km above the ground. These are dominated by crystals.
They may be of following types:
a. Cirrus– They have fibrous or hair like appearance. They consist of tiny ice crystals, and indicate fair/ dry weather. They are also known as “mares tails” .
b. Cirro- cumulus– These clouds appear as small globules or ripples arranged in groups.
c- Cirro- stratus– These clouds appear to be spread in the sky like thin white sheets. They are too composed of tiny ice crystals which refract light. Due to this refraction, characteristic ” halo” are created around sun & moon.
2- Medium clouds– They form at about 2-6 KM above the sea level. They consist of both ice crystals and water vapors.
They are of following types :
a. Alto-cumulus – They appear as woolly or globular clouds arranged in layers. They indicate fine weather.
b- Alto-stratus– They appear grayish and dense clouds having fibrous or uniform look.
3- Low Clouds– They form at less than 2 km height above the ground.
They are of following types :
a. Strato-cumulus– They appear as bumpy clouds, denser than the alto-cumulus clouds. Generally they are associated with fair or clear weather, but occasional rain can be seen.
b. Stratus Clouds– They can be seen as uniformly grey and thick. It brings dull weather and occasional drizzling. They form a fog like condition, thus reducing visibility thereby are dangerous for aircraft’s.
c. Nimbo-status- These clouds cover a wide area and produce rainfall( Rain/ Snow/ Sleet ). They are basically rain clouds. These are dark,and dull colored. They are not accompanied by lightning, thunder or hailstorm.
4- Clouds with great vertical extent/ Vertical Clouds – They have no definite height. These clouds can have any height ranging from 1- 9 km.
a. Cumulus– These are vertical clouds with rounded top and horizontal base. They don’t have sufficient atmospheric conditions to produce rainfall. They indicate fair weather.
b- Cumulo-nimbus clouds– They are over grown cumulus clouds. It often have a ‘cauliflower’ like shape. These are also known as “thunder clouds”. These are associated with cyclones and storms. They bring torrential rainfall always associated with lightning and thunder.