You may not know them by name but you definitely know what they look like. Cumulus clouds are the clouds we all drew as kids, they are the cotton ball clouds you see in the intro to The Simpsons.
They come in many different shapes and sizes and are generally the easiest clouds to pick out in the sky. Whenever the average person is asked to visualize a cloud the cumulus is the cloud that generally will be the first to come to mind.
In this article we will tell you all about the cumulus cloud (see also ‘All You Need To Know About Asperitas Clouds‘), where it sits in our sky, its many forms and when they typically occur.
Cumulus Cloud Species
As we have already mentioned cumulus clouds come in many different shapes and sizes and can be described by their four different species.
If the cloud you are looking at is wider than it is tall it is a cumulus humilis. If the width is the same as the height then it is a cumulus mediocris.
But, when a cloud is taller than it is wide then it is known as a cumulus congestus and when this cloud is in the sky things will get interesting.
If cumulus congestus clouds continue their vertical growth they become capable of producing rain and can eventually morph into a cumulonimbus cloud, these clouds are mostly known for carrying thunderstorms.
If the cloud’s vertical growth is high enough then you may see a cloud that looks like a cap on top this is known as a pileus cloud.
Whilst cumulus clouds are more commonly low level clouds, cumulus congestus with the right vertical growth will reach into the middle level of the troposphere.
The final species of cumulus clouds is the cumulus fractus, these clouds are ragged and broken up. You will typically see these clouds in the evening sky as cumulus clouds begin to dissipate, they can also be spotted on windy days.
Cumulus Cloud Details
One of the most unique clouds the cumulus cloud has many peculiar details the first is the level the cloud sits at. Cumulus clouds sit low in the troposphere typically ranging from 2-7,000 feet.
However the congestus can reach much higher and form into a new type of cloud.
The name cumulus derives from the latin term cumlo- meaning heap.
When you see the cloud in the sky it will mostly be white however when carrying precipitation the cloud will turn a gray color, cumulus clouds can carry precipitation that turns into rain once the cloud releases the water.
However, cumulus clouds do not typically carry precipitation and it is considered uncommon for them too. These clouds will cover the sky when it is a sunny day but either won’t form or are rare on rainy days.
When the conditions are right however the sky will be full of cumulus clouds, they are considered to be very common amongst cloud formations when the sun is out and it is a sunny day.
The cloud has only one associated variety named cumulus radiatus. This occurs when the clouds form parallel bands in the sky looking like traffic at rush hour on the highway.
They form in strips in the sky and appear to converge when looking at the horizon. Often they are referred to as cloud streets.
Cumulus Cloud Features
There are five features associated with cumulus clouds: arcus, flucts, praecipitatio, tuba and finally virga.
Cumulus arcus are clouds more commonly known as shelf clouds; they can be more easily identified by their wedge-shaped formation and are often accompanying a thunderstorm.
Cumulus fluctus are identified by their distinctive curled appearance that looks like a crashing wave. They are created when the wind causes the top of the cloud to move faster than the bottom giving the wave effect.
Praecipitatio is the term for when a cloud is accompanied by either rain, snow, sleet or any other type of precipitation that will reach the ground. It is only named praecipitatio when the precipitation makes contact with the ground.
A tuba is most commonly known by their other name ‘funnel cloud.’ Funnel clouds are formed by condensed water droplets that form around a spinning column of air. The most popular type of funnel cloud is the tornado that is produced from strong thunderstorms.
Finally we have the cumulus virga. These cloud formations are rain and precipitation strips falling from a cloud that evaporate before they reach the ground.
They can be found on the edge of rain or snow showers that are approaching. Virga’s look like cloud wisps falling from the base of the cloud they are attached to.
Clouds that exhibit virga are known as jellyfish clouds and their name can be interchanged with the term ‘fallstreak.’
Hi, my name is Andrew Capper and I have been a meteorologist for almost 30 years now. My line of work specializes in the scientific principles used to explain and understand the earth’s atmosphere and how that affects everyday life.
I created this website to share my knowledge and help others stay safe during extreme weather events.
I’ll be looking at weather forecasting, clouds, tornadoes, hurricanes, and much more - so, if you’ve ever been fascinated by the weather like I have been since I was a young boy, this is the site for you. Enjoy!
