What is Cloud Seeding?

May 9, 2024

The Supreme Court recently told the Uttarakhand government that cloud-seeding would not douse the forest fires that had claimed five lives in the State.

Why Cloud Seeding is done?

Water vapour condenses around small particles to form the droplets that make up a cloud.
These droplets collide and grow; as they get heavy and the cloud gets saturated, it rains.
Not all clouds create rain. Even if they do make rainwater, only a few clouds are able to produce enough moisture that allows for large raindrops.
- This may happen because there aren’t enough ice particles within a cloud.
- Because of this, there aren’t enough cloud droplets to combine and make raindrops.

What is Cloud Seeding?

It is a scientific process that improves a cloud’s ability to make rain or snow, as well as control other weather events.
It is the deliberate introduction into clouds of various substances (seed) that act as condensation nuclei or ice nuclei in an attempt to induce precipitation.
Cloud seeding gives these clouds a lot more ice crystals (or cloud nuclei). It has been performed from aircraft, rockets, cannons, and ground generators.
Many substances have been used, but solid carbon dioxide (dry ice) and silver iodidehave been the most effective. When used in supercooled clouds (composed of water droplets at temperatures below freezing), they form nuclei around which the water droplets evaporate.
The resulting water vapour deposits into ice crystals, which build quickly as water droplets attach themselves.
Right after, the ice crystal becomes a heavy, large raindrop, it will then fall through the cloud and onto the ground as rainfall.
Conditions Required:
- Cloud seeding requires existing clouds, and not all types of clouds are suitable for seeding.
- Clouds must be deep enough and of a suitable temperature (between -10 and -12 degrees Celsius) to be seeded effectively.
- The wind must also be below a certain speed. These conditions are most common in mountainous areas.
Benefits: It is used all over the world as a method for enhancing winter snowfall and increasing mountain snowpack, supplementing the natural water supply available to communities in the surrounding area.