Cloud seeding: What it can and can't do for water shortages

Michael Krumboltz
Michael Krumboltz
The Sideshow

Want more snow? Probably not, if you're on the East Coast. But in drought-prone Arizona, they're working on it.

The Central Arizona Project (CAP), the agency that controls and operates the canal that redirects water from the Colorado River into Arizona, is researching snow-making techniques made possible by cloud seeding, reports. The project could pump up Arizona's water supply by 5 to 10 percent.

Cloud seeding is not a particularly new technology, but the science of it today "is substantially different than what folks were doing in the '70s, when cloud seeding was oversold as a technology," Chuck Cullom, a geologist and CAP's Colorado River program manager, told Yahoo News.

But does it work? Cullom said he's careful about exaggerations, but "the state of the science and the state of the technology today indicates that a well-operated cloud seeding program can increase snow production in a storm. The peer-reviewed science journal articles support that statement. That wasn't true 20 years ago."

What's changed? "The reason it's different is we have better instruments that tell us which clouds [and] which storm events are susceptible to improving their snow productivity."

That's not a cure for lack of rain, though, Cullom said. "Cloud seeding is not a drought buster. Its focus is on increasing normal year snowpack. We're making the snow formation in the cloud more efficient."

The generators that produce an aerosol that acts as a catalyst are based on the ground. When placed on a high enough surface, like a mountain, they can almost touch the bottom of a cloud. "We just turn on the generators to introduce the aerosol and start the snow formation or increase the snow formation."

The process doesn't produce moisture, however, or make clouds. "Cloud seeding doesn't stop a low snow year, but it can make a normal year better and a dry year not so horrible," Cullom said.

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