Clouds may be something we don’t pay much attention to, but when thought of on a universal scale, they are among the most interesting features of the planet we call home because not every planet has clouds. But here on Earth, the constantly shifting and evolving patterns of clouds play a significant role. [1]

“Different kinds of clouds have different effects on temperature; they cool or warm the Earth below.”

Aside from simply looking magnificent, clouds are among the key regulators of Earth’s global temperature. Different kinds of clouds have different effects on temperature; they cool or warm the Earth below.

Some clouds are responsible for helping to cool the Earth. They intercept rays of sunlight, and either disperse the energy across a large surface area or reflect it back towards the sun. Both effects help to cool the planet. [1]

Other clouds are able to warm the Earth because they trap heat like a blanket on a cold night. These insulating clouds prevent heat from leaving through the atmosphere, maintaining a warmer temperature. [1]

Clouds aren’t only able to affect temperature. Storm clouds, for example, are responsible for creating more noticeable changes in the weather. Aside from causing rainfall and lightning, storm clouds also help disperse energy across the planet from warm areas near the equator down to the icy poles. [1]

So, although clouds may be far away, given that they exist high above us in the atmosphere, they become an essential component of our daily lives through influencing the weather. Thus, it’s essential to demystify clouds, which we will do in this article by exploring different cloud types.

An average cumulus cloud (the fluffy white cloud type) weighs the same as a jumbo jet - about 500 tonnes.

Cloud Formation

Clouds form when air vapor reaches what is known as the saturation point. Simply put, this is when the air is holding as much moisture as it can, or when it is saturated. [2] This can happen through either evaporation or condensation.

Evaporation can cause cloud formation because as water is absorbed into the air, the humidity or water content of the air grows. This means that the saturation point is reached when the moisture level has reached a maximum volume. [2]

Condensation can cause cloud formation by having absorbed moisture condense out of vapor. This occurs when the air cools, which creates liquid water droplets out of the moisture-rich air. [2]

Altitude plays a strong role in the formation of different cloud types, as well as their function and effect on daily life. The naming of cloud types also partially depends on their altitudes. We will explore this concept more in a short while.

The word “cloud” comes from the Old English words “clud” or “clod” meaning lump of land or lump of rock. In the 13th century, the meaning was extended to apply to the lumps of water in the sky.

Three Main Cloud Types

When talking about cloud types, it's important to understand how they interact with the atmosphere at different altitudes. Each type of cloud is defined by its shape and size, and each type has a distinct relationship with the weather.

Cumulus Clouds

These are the clouds that most people think of when imagining a cloud—distinct, fluffy puffs of vapor. These clouds are common all over the world with the sole exception being frosty Antarctica, where it’s too cold for the liquid water that composes these clouds to exist. [3]

These clouds are formed through currents in the air as a result of thermal convection, which occurs when hot air rises until it cools and forms water droplets. As a result, cumulus clouds are often seen in the middle part of the sky in good weather. They occur when the sun is shining enough to warm the earth and subsequently create warm air on the ground. This air then rises through the atmosphere and forms convection currents. [3]

Stratus Clouds

These clouds are formed through advective cooling, when warm air suddenly travels into a colder location like above the sea or throughout mountains. When these clouds are below 50 ft above the surface of the Earth, they’re often called fog. [3]

Stratus clouds are also common worldwide, and may contain small amounts of rain. However, they’re unlikely to give off more than a light drizzle. [3]

Stratus clouds can join with cumulus clouds to become stratocumulus clouds. These are a semi-continuous layer of clouds with the fluffiness of cumulus clouds and the connected shape of stratus clouds. [3]

Cirrus Clouds

Cirrus clouds are the final of the three main groups. They’re distinct in that they’re made of solid ice crystals. These clouds form the highest of all cloud groups and, as such, are also exposed to high winds. These winds disperse the ice crystals to give the signature wispy look of a cirrus cloud. [3]

Cirrus clouds are also important for weather but have no precipitation that reaches the ground. [3]

The psychological phenomenon of seeing objects in clouds is called pareidolia.

Special Cloud Types

Clouds Defined by Their Altitude

Clouds can be defined by their altitude, as explained earlier. Clouds very high in the sky are given the prefix cirro-, which can be confusing as “cirrus” is also a type of cloud. For example, a cloud with its stratus shape high in the sky is often dispersed into a light, milky mist, which is called a cirrostratus cloud.

Clouds in the middle range of altitude are given the prefix alto-. Altocumulus or altostratus clouds are distinct shapes within the middle range of altitude.

Low clouds don’t have a special prefix. They’re always just stratus clouds.

Rain Bringers

A nimbostratus cloud over a field.

Another subtype of cloud is the nimbus. These are the clouds that bring rainfall and can have either a cumulus shape (cumulonimbus) or a stratus shape (nimbostratus).

Unique Clouds 

While we’ve covered the three most common cloud types (and then some!), you may also occasionally spot some different clouds.

Lenticular clouds above a mountain.

Lenticular clouds often stand out as they look like UFOs. These flying saucer shaped clouds are usually formed over mountainous terrain. [4]

Mammatus clouds over a field.

Another interesting cloud type is mammatus clouds. These clouds include small bulging pouches underneath other clouds, often in a line or series. [5]

Clouds and Weather Predictions

As we’ve already learned, some clouds are associated with different types of weather. For example, spotting a cumulus cloud means rain is unlikely. However, spotting a cumulonimbus cloud means rain is almost certainly on the way.

Although weather prediction is possible from simple cloud spotting, it’s hard to do well without practice, which is where weather prediction apps can be helpful.

You could call a clear blue sky cloudless or, if you want to impress someone, you could call it enubilous.

Predicting Weather Using Clouds with Sonuby

Predicting weather using cloud coverage is difficult, and for specialty clouds, it’s nigh impossible. But using a weather app can help get you more accustomed to cloud patterns associated with certain weather types and help you hone your weather prediction skills.

The “Daily Life” report in Sonuby is a great tool as it offers weekly meteogram and cloud coverage maps. This means you can check the forecasted weather and cloud formations and then check them against your own predictions based on the clouds you observe on the day.

Pictograms are also offered in the hourly forecast of Sonuby, which can show off cirrus clouds as small feathery elements.

 

References:

[1] https://www.nasa.gov/pdf/135641main_clouds_trifold21.pdf

[2] https://www.weather.gov/source/zhu/ZHU_Training_Page/clouds/cloud_development/clouds.htm

[3] https://www.epfl.ch/labs/lapi/wp-content/uploads/2020/03/Clouds.pdf

[4] https://www.metoffice.gov.uk/weather/learn-about/weather/types-of-weather/clouds/other-clouds/lenticular

[5] https://www.metoffice.gov.uk/weather/learn-about/weather/types-of-weather/clouds/other-clouds/mammatus#:~:text=What%20are%20mammatus%20clouds%3F,hanging%20from%20the%20cloud%20above.

Fact box: https://www.csiro.au/en/news/all/articles/2017/february/no-fluff-here-10-little-known-clouds-facts#:~:text=An%20average%20cumulus%20cloud%20(fluffy,enough%20to%20keep%20them%20up.

This post is part of Sonuby's Weather Wednesdays series, where we discover exciting weather phenomena and interesting facts about the weather. Subscribe to our newsletter to receive posts like this one in your inbox.

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