Basic Cloud Forms
Determine the difference between low, middle and high cloud types
The sky presents many magnificent cloud displays to see. Learn more if you are a curious hiker, cloud chaser or have been finding animal shapes in the sky for years.
Clouds are not straightforward, in fact they are ever changing as the world turns and air currents rise or fall. Their beauty has captivated artists, poets, writers and scientists since there were such people as artists and poets. Perhaps you have looked into a sunset of fluffy clouds lit orange, pink and purple by the suns setting rays or looked into the heavy grey low-lying clouds with dread as you put on a rain jacket. Knowing what you are looking at is not only enjoyable, but may help you predict weather that’s around the corner.
Low Clouds: generally 2,000 feet and above
One of the clouds people are probably most familiar with is the Cumulus. These are the fluffy, cotton-candy clouds that look like heaps of cotton and its name is Latin for ‘heap.’ These clouds will form over land starting small and develop vertically in rising towers. These clouds generally do not bring precipitation.
As these clouds build in the atmosphere, once they reach above 40,000 feet they tend to morph into the Cumulonimbus or thunderheads. The top of this cloud is often spread out in an anvil shape as it hits the troposphere. This huge dark cloud can unleash downpours, hail, snow, lighting, tornadoes and hurricanes.
Stratus clouds can start at the ground level and often evoke feelings of melancholy as they create a veil of fog. These blankets that cover the sky were inspiration for the movie, The Fog and are most likely to occur near coasts and mountains.
Stratocumulus look like a mix of the individual puffy Cumulus and the solid layer of Stratus, like a giant sprawling blanket of connected puffy clouds that occasionally let light through.
Middle Clouds: generally 6,500 feet and above
Altocumulus are usually found in a layer or patch of cloudlets which often look like long strips of cotton stretched out, though this cloud can also form into the UFO shaped lenticularis.
Altostratus is a very uniform mid-level grey cloud. In fact it doesn’t vary much and so there are no species within this one. Usually the sun can be seen as a fuzzy round glow through from behind this vast cloud.
The Nimbostratus is just as dreadful as it sounds. This steady dark blanket of a cloud issues continuous heavy rain, much longer than the Cumulonimbus’s short snappy storms.
High Clouds: generally 16,500 feet and above
Cirrus or the commonly called mare’s tails are the wispy high white clouds which may look as if they have been brushed onto the sky by a painter’s hand. Cirrus is Latin for ‘lock of hair’ and looks just as delicate. These are formed by ice crystals above the troposphere and are elongated as the clouds descend and the ice crystals drag behind.
Cirrocumulus is the grainy looking sky also referred to as ‘mackerel sky.’ The individual clouds making up this formation may be the same size as the Cumulus but because they are so high up they appear as smaller particles.
If you have ever seen a halo around the sun, it may have been the Cirrostratus. This pale and high cloud is formed of ice crystals and never thick enough to block the sun. These mythical looking clouds can create arcs of slight rainbow from the light rays bending through its ice crystals.
Of course these aren't the only types of clouds. Each Genus of cloud mentioned has several species and varieties. If your interest is more of an infatuation, you may consider becoming a member of the Cloud Appreciation Society.
Reference:
(1) Pretor-Pinney, Gavin. The Cloud Spotter's Guide: The Science, History, and Culture of Clouds. New York NY: The Cloud Appreciation Society, 2006.
