Science a GoGo's Home Page Forums General Discussion Climate Change Forum Cloud Seeding

Does cloud seeding happen any more?

Today we have a lot of cloud after a reasonable fall of rain last night (our first in this area for about 4 weeks). I seem to remember that in the 60s(?) there used to be cloud seeding and rain would often follow. Then the weather here became wetter through the 70s and 80s and cloud seeding was no longer carried out. The 90s and 2000s-on have been very dry and now we are so far into dreadful drought that there is talk of completely evacuating 2 towns in SW Queensland. (Climate Change or drought??? that's a big debate here). Then I heard cloud seeding mentioned for the first time in ages on a programme on Climate Change and I wondered why seeding had stopped.

So here are my queries--- Does cloud seeding work?---Is it done anywhere these days?--- And if it does work, why was it stopped?

From: North American Weather Consultants, Inc.
http://www.nawcinc.com/wmfaq.html

"---Cloud Seeding Frequently Asked Questions---"

"Is cloud seeding effective?

...For precipitation augmentation, the accepted magnitude of increase to be expected from well-designed and properly conducted projects ranges from 5% to 20% for winter precipitation in continental regions and from 5% to 30% for coastal areas. For warm season precipitation increase, single-cloud experiments have indicated increases as large as 100%. Area wide increases over a project area vary with the frequency of occurrence and spatial coverage of suitable cloud systems, plus the ability to treat all favorable clouds. Hail suppression effectiveness, based upon surface hail data, is estimated to be in the range of a 20-50% reduction."

"How widely used/accepted is cloud seeding technology?

Over its history of 50 years, modern cloud seeding has involved projects of various types in nearly 50 countries around the world. Some individual projects have been in operation nearly continuously for decades, with a few operating for nearly fifty years. As water needs increase world-wide, the demand for weather modification services will also increase. Similar increase in demand will occur in hail-prone regions."
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From: BBC News, Thursday, 17 March 2005
http://news.bbc.co.uk/2/hi/asia-pacific/4358535.stm

"Thailand's King Bhumibol Adulyadej is to oversee personally an artificial rain-making project in a bid to end a severe drought in the country..."

It's been used in Thailand this year. I'm told that it worked, but I don't know how well. From what I've read, the chemical used was probably Silver Iodide.

Ellis wrote:

"Today we have a lot of cloud after a reasonable fall of rain last night".

Even made TV news over here. As for your query re. cloud seeding: I haven't a clue. Rede, thanks for your links.

Thanks Rede--It was silver iodide that was used here in the 60s. I was wondering if perhaps the chemicals they used had been proved harmful but if they are using it still thsn perhaps it is not so.

We watch the Rugby terry and your green, green football grounds nearly make us cry!!!
But we had a bit more rain last night.

Ellis. I lived in the Blue Mountains for about four years. Played in bands west as far as Bathurst so know the colour of the Australian landscape. Not as green as NZ but NZ's not as green as Ireland. You get sick of green all the time anyway. My brother has just gone back to OZ so he will be pleased with more rain. He's up near Echuca on the Murray.

I come from Wales, it rained every day and never thought I could long for rain ever!