Tag Archive | clouds

Making it Rain


In Tasmania our electricty comes from Hydro Tasmania. A Renewable energy source which uses water Turbines to create Electricity. There are huge manmade catchment lakes built throughout the Central Plateau areas to give a ready supply of water to keep the power on.

So how does it work?

Here in Tasmania, as well as in the Snowy Mountain Regions of New South Wales, use a method known as Cloud Seeding. 


 Cloud seeding was first demonstrated by Schaefer from the General Electric Laboratories on 13 November 1946. The first case of documented man-made rain occurred near Bathurst, Australia in February in 1947 by CSIRO (Commonwealth Scientific and Industrial Research Organization – Australia).

This works by Flying into Cumuliform Cloud or Stratiform Cloud and depositing one of three substances in the Clouds:

Silver Iodideis very similar in structure to naturally occurring ice. Water deposits form on the surface of the silver iodide crystal and the ice crystals continue to grow as if they were naturally occurring ice crystals.

Dry Ice (CO2)acts to cool the water far beyond 0ºC thereby causing the cloud droplets in the air to freeze, thus growing as water freezes on the surface of the ice.

Hygroscopic saltsSalts (KCl, NaCl) attract the water vapour to themselves, growing larger and eventually forming into raindrops.

Hydro found that Silver Iodide is the most suitable but also can use Dry Ice.

So why not use this method to save the rest of the country from drought you may ask, I know I did:

Unfortunately not all clouds are suitable.

  • Significant levels of supercooled liquid water have to be present in the cloud.
  • The cloud must be deep enough and the temperature must be within a range suitable for seeding.
  •  The wind also has to be below a fixed value.
  • Once all the criteria are met, cloud seeding can be successfully utilised to produce rainfall.

So does Cloud Seeding Affect Rain Fall to the area outside the seeded areas?

The Short answer is NO! it does not appear to affect rainfall but please Read the report below to find out more:

The Australian Cloud Seeding Research Symposium concludes on 9 May, 2007.

The Big Question is

“IS IT HARMFUL to the environment and Humans?”

This is a huge questions. I was listening to the ABC Radio 2 weeks ago when I heard that Cloud Seeding was possible responsible for an increase in Ammonia levels heres the article:

Snowy Hydro rejects cloud seeding pollution claim

Posted Fri Oct 12, 2007 12:19pm AEST
Updated Fri Oct 12, 2007 12:18pm AEST

Snowy Hydro is casting doubt on a study that blames cloud seeding for polluting New South Wales high country lakes.

National parks and wildlife ecologist Dr Ken Green has told a Jindabyne meeting that the $20 million cloud seeding trial might be linked to a big increase in ammonia levels in alpine waterways.

Dr Green says the increased ammonia had already caused algal blooms, high nutrient levels and changes in acidity.

But Snowy Hydro spokesman Paul Johnson says there is nothing to back up the claims.

“Snowy Hydro is yet to see any scientific basis or data in relation to those statements,” he said.

“I think you have to take that into account and understand in the absence of any reporting data these claims by Dr Green are not scientifically sound at the moment.”

So This may well be the future for our water, for our farms and could well help solve the problems of Renewable energy and drought in the years to come.

What do you think?