How Are Clouds Formed?

Look up at the sky on any day and there are chances that you'll almost always spot a cloud. Some clouds are white and puffy while others are very thin. Some of them are dark and full of rain. But have you ever stopped to think about what a cloud actually is, and how it gets up there? Let's break it down, step by step, in the simplest way possible and how clouds are formed. 

How Are Clouds Formed?

Step 1: Water Turns Into Vapour

It all begins on the surface of the earth which is in the rivers, in the lakes, in the seas, even in damp soil.

When the sun heats water, the water slowly converts to an invisible gas, known as water vapour. This process is known as evaporation. It cannot be seen, but it is occurring everywhere and all the time. This water vapour floats up into the sky.

Step 2: The Air Rises and Cools Down

Warm air is less dense than cool air, and naturally rises upward. The further it climbs up, the following things happen:

• The air pressure drops

• The air starts to cool down

The crucial part is that there is a limit to how much water vapour can be contained in cold air as compared to warm air! As the air cools off all that water vapour it carried begins to search for a place to go.

Step 3: Dust Plays a Surprise Role

Water vapours simply don't turn into water droplets. It requires some minute particle in the air to cling to, a particle of dust, or smoke.

The small particles are called condensation nuclei. If you could see a cloud up close, you would notice that every water droplet has one of these particles in the centre. It is a small speck of dust or smoke around which the water vapor is wrapped.

Step 4: Droplets Come Together And Cloud is Born

When the water vapour clings to these little dust particles it forms a water droplet. One drop is not visible. But all the billions of them together? That's what we see as a cloud.

These droplets turn to ice if it is cold enough at high elevation. Clouds high in the sky, such as the thin ones are actually made out of ice.

Step 5: Rain Comes Back Down

As time passes, the droplets in the cloud bump into each other and stick together and that is how clouds grow bigger and heavier. As they grow heavier, they fall back to the ground as rain, snow, or hail.

And then the whole cycle starts again.

What Are the Three Levels of Clouds?

Clouds are grouped by how high they are in the sky:

• Low clouds (less than 2,000 metres) such as clouds of stratus and cumulus. These are the ones you come across the most.

• Mid level clouds (2000 to 6000m) such as altocumulus and altostratus. Gray in color and typically distributed around the sky.

• High clouds (> 6,000 metres) such as cirrus. White, thin and in the form of ice crystals.

Why Do Clouds Matter?

Clouds are a part of something called the water cycle — the never-ending journey water takes between the Earth and the sky.

Water evaporates from rivers, lakes, and oceans and rises into the sky as vapor then cools and condenses into clouds and finally falls back as rain or snow which makes it flow back into rivers and oceans and the whole thing starts over again.