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Cloud seeding potential exists in Arizona, per new report

The Salt River Project is studying the feasibility of winter cloud seeding in the White Mountains
Clouds roll over the snowy Santa Catalina Mountains after a winter storm hit Tucson.
Posted at 7:01 PM, Apr 20, 2023

TUCSON, Ariz. (KGUN) — It’s not happening yet in Arizona, but cloud seeding is already making an impact in the state.

The process involves finding clouds under the right weather conditions—such as moisture, temperature, and direction of movement. Then, silver iodide particles are launched into those clouds, either from the ground or a plane.

“The best way to think about it is improving the efficiency of the cloud,” said Central Arizona Project planning analyst Nolie Templeton. “The cloud has so much moisture that is within the cloud. And what the silver iodide can do is mark those particles a little bit heavier, so then they’d fall out of the cloud.”

The strategy is several decades old, and has been used frequently in other Western states.

CAP helps fund cloud seeding programs in the Upper Colorado River Basin, in Colorado, Wyoming and Utah.

A CAP study that began in 2007 in partnership with Wyoming agencies found the practice to be effective there, adding to the water that eventually flows into Arizona via the Colorado River.

“We felt pretty comfortable that there was about a five to 10 percent increase in precipitation, stemming from that study,” Templeton told KGUN.

CAP partners with other Lower Basin agencies in Nevada and California to send up to $1.5 million each year to seeding projects in the Upper Basin.

The Associated Press reports even more investment there, including a new $2.4 million federal grant… and more than $14 million in next year’s Utah state budget.

“If this is a way to increase the snowpack, even if it’s incremental, then it’s something that we need to look at and consider,” said Templeton.

She added that there are safety procedures attached to the projects that CAP funds; if snow water equivalents reach certain thresholds, seeding operations are suspended to prevent too much snow or flood concerns.

But would cloud seeding work on clouds in Arizona? The discussion has gained momentum in recent years.

The Salt River Project has been researching the feasibility of winter cloud seeding in the White Mountains, in partnership with the White Mountain Apache Tribe. A climatology report is being finalized.

“What we’ve learned about that area, using observed weather station data and high tech, the latest and greatest weather modeling… the cloud seeding potential is on the same order as most of the other Western states,” said SRP meteorologist James Walter, who points to

But Walter says there still needs to be more measurements in the clouds to see if they match model data from the initial report. He says there also needs to be community education and discussion as well as approved permits before a trial program can get off the ground.

Walter adds that there is a group in Pinal County assessing the potential for cloud seeding summer thunderstorms.

Even if or when these plans become reality, experts say cloud seeding is not planting a miracle cure for drought.

“It’s one tool in the toolbox,” said Templeton. “Some way that we can hopefully augment some snowpack in some years given the correct conditions. We don’t wanna take away from the message that those other tools in the toolbox also need to be utilized.”

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Ryan Fish is an anchor and reporter for KGUN 9 and comes to the Sonoran Desert from California’s Central Coast after working as a reporter, sports anchor and weather forecaster in Santa Barbara. Ryan grew up in the Chicago suburbs, frequently visiting family in Tucson. Share your story ideas and important issues with Ryan by emailing or by connecting on Facebook and Twitter.