New Study Shows Cloud Seeding Works

That’s what this article from Water Deeply says and that is really great news.

An excerpt.

Cloud seeding has become big business worldwide as a means to boost water supplies. Utilities and governments spend tens of millions of dollars on the process, which is especially common in Western states that rely on winter snowpack to meet year-round water demand.

The basic process involves spraying silver iodide from a plane as it flies through storm clouds. The silver iodide induces moisture in the cloud to form ice crystals, which then (hopefully) fall out as snow.

Some studies have estimated cloud seeding can boost snowfall by between 8 and 15 percent. This figure was derived by comparing snow depth on mountains beneath clouds that were seeded, compared to nearby mountains in unseeded areas affected by the same storm. And it was deduced that seeding made the difference.

But amazingly, the basic physical process believed to occur during cloud seeding has never been conclusively proven. No scientist has ever verified that silver iodide causes ice to form in a cloud, and that the artificially created ice then reaches the ground as snowfall.

Until now. In a new study, a team of scientists led by Jeffrey French at the University of Wyoming in Laramie has proven the entire chain of events, from ice formation in the cloud to snow accumulating on the ground as a direct result.

The study does more than simply prove conventional wisdom. French, an assistant professor of atmospheric science, tells Water Deeply that dissecting and verifying the process will help make cloud seeding more effective.

Water Deeply: What did you prove in this study, exactly?

Jeffrey French: What we showed was that in certain conditions, when you add silver iodide to a cloud, you can get the cloud to nucleate ice particles that otherwise would not. So you’re freezing some of the supercooled liquid that otherwise would remain a supercooled liquid, in conditions that would then allow those newly formed ice crystals to grow through a variety of natural cloud processes to a point that they are large enough to then fall out of the cloud and land on the surface of a mountain as snow.

We were able to document that entire process, and that’s never actually been done before. Nobody has ever been able to probe into it repeatedly with time and look at the evolution of the cloud particles. And that’s what we were able to do.

Water Deeply: Why is it important to verify this process?

French: It’s important to be able to evaluate whether cloud seeding is really having an impact. The big question is, at the end of day, are you putting more snow on the ground in any significant amount? It’s a statistical question and it’s an area question. It’s done through looking at correlations, between times when you seed and how much snow falls and times when you don’t and how much snow falls. The problem with that approach is that there is so much natural variability in the world that you can have what appears to be a positive signal, but it may come up just by pure chance or there may be other impacts that cause you to have more snow at these times versus other times.

Retrieved February 16, 2018 from

About David H Lukenbill

I am a native of Sacramento, as are my wife and daughter. I am a consultant to nonprofit organizations, and have a Bachelor of Science degree in Organizational Behavior and a Master of Public Administration degree, both from the University of San Francisco. We live along the American River with two cats and all the wild critters we can feed. I am the founding president of the American River Parkway Preservation Society and currently serve as the CFO and Senior Policy Director. I also volunteer as the President of The Lampstand Foundation, a nonprofit organization I founded in 2003.
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