Cloud Seeding In RivCo On Hold Until 2025

MURRIETA, CA — A weather modification program that utilizes "cloud seeding" to, ideally, increase precipitation and generate more water for the Santa Ana River Watershed will not be restarted until a year from Friday, though the debate over whether the program has value, or potentially negative impacts, will likely continue.

The Santa Ana Watershed Project Authority, a multi-agency cooperative that focuses on groundwater management in the Inland Empire and elsewhere, initiated its "Cloud Seeding Pilot Project" last November, deploying dispersal units in select locations to pump out streams of silver iodide when storms arrive, with the goal of producing up to 15% more precipitation than might otherwise fall in the region.

"The water supply benefits in recharging groundwater occurs in both wet and dry years," SAWPA General Manager Jeff Mosher told City News Service. "Additional precipitation benefits soil moisture in forested areas and habitats due to additional stream flows."

The $1.2 million program, paid for in part by a California Department of Water Resources grant, was inaugurated on Nov. 15, 2023, following feasibility studies and a California Environmental Quality Act report that found no significant threats posed by the silver iodide particles disseminated via propane-powered cloud nuclei generators. The inaugural year's dispersals ended on April 15.

Just over a dozen units were activated for "flaring" during 13 storm systems, according to SAWPA's 2023-24 report on the program. The ground- based devices were strategically placed along the boundary of the Cleveland National Forest, aimed toward Corona, Temescal Valley and Lake Elsinore, as well as at the foot of the San Jacinto Mountains in the Anza Valley, and the San Bernardino and San Gabriel Mountains to the north.

"Overall, the program ... worked well with the weather patterns observed during the season," the report stated. "The sites appeared to be effective at targeting their seeding material properly."

There was no estimate of how much difference the units made in ramping up precipitation.

The concept of pumping silver iodide into the lower atmosphere for weather modification is not new -- and not without debate. During the Vietnam War, the U.S. military implemented "geoengineering" as a weapon, according to Popular Science. Its expose on "Operation Popeye" detailed how airborne cloud seeding was used to invigorate monsoonal rains to hamstring North Vietnamese troop movements by saturating their logistics supply lines with mud and floods.

Seeding programs have been widely used in civilian operations worldwide since that time, from Idaho and Colorado to China and the United Arab Emirates, according to published reports. The activity is described by SAWPA and other agencies as "safe" and "reliable," but longtime Bay Area meteorologist Brian Sussman, author of the recently released book "Climate Cult," pointed out that silver iodide is defined by the U.S. Environmental Protection Agency as a "hazardous substance."

"It's been deemed hazardous by the Clean Water Act, and numerous studies conclude repeated use in the same geographical area is not advisable," Sussman told CNS. "What has changed in the Santa Ana River Watershed is not the climate, but the human population and its need for more water. Modifying the weather to yield more precipitation may be successful, but it is fraught with uncertainty."

Riverside-area resident Colleen Strong voiced her concerns about the program during a Riverside County Board of Supervisors' meeting earlier this year, saying she was "caught" in a storm during which seeding occurred in early March.

"There was a horrific hail and thunderstorm on the 215 freeway that caused several accidents," Strong said. "I found out afterward that it had been a cloud-seeded event. They were trying to induce that on Easter Sunday, too, when we had a Sunrise Service, which is very alarming to me."

Murrieta resident and environmental activist Catherine Fischer told CNS she is opposed to all forms of geoengineering.

"The impacts of this are too numerous to list," she said. "I think that God did a wonderful job creating the weather, and we should just leave it alone."

Mosher said SAWPA's environmental impact report confirmed "the impacts of silver iodide ... are less than significant."

"Silver iodide would not result in iodide or ions in the environment in sufficient quantities to harm sensitive ecological receptors," he said. "Studies have shown that cloud seeding does not result in concentrations of silver iodide in the environment that would be toxic to humans or wildlife."

According to SAWPA's contractor for the project, North American Weather Consultants, conditions necessary for productive seeding include non- erratic winds, high moisture content and freezing or slightly subfreezing temperatures. Mosher said operations are suspended when seeding might contribute to "flooding and debris flows," such as during "large storms and multiple storms occurring in a short time frame."

He said the agency communicates with regional flood control districts to gauge whether landscape disturbances caused by wildfires could pose risks. The burn scars left by summer blazes in the San Bernardino National Forest and Cleveland National Forest prompted suspension of all seeding operations this season, resulting in the postponement to Nov. 15, 2025.

Sussman said the National Academy of Sciences published research 20 years ago raising doubts "regarding the effectiveness of cloud seeding."

He noted that if Southern California slips back into substantial drought, seeding would be "generally ineffective" no matter how much silver iodide is pushed skyward.

For more information, visit sawpa.gov.