Two days before the waters of the Guadalupe River swelled into a deadly and devastating Fourth of July flood in Kerr County, Texas, engineers with a California-based company called Rainmaker took off in an airplane about 100 miles away and dispersed 70 grams of silver iodide into a cloud.
Their goal? To make it rain over Texas — part of a weather modification practice known as cloud seeding, which uses chemical compounds to augment water droplets inside clouds, making the drops large enough and heavy enough to fall to the ground.
But in the hours after the flood swept through the greater Kerrville area and killed at least 135 people, including three dozen children, conspiracy theories began swirling among a small but vocal group of fringe figures.
“I NEED SOMEONE TO LOOK INTO WHO WAS RESPONSIBLE FOR THIS … WHEN WAS THE LAST CLOUD SEEDING?” wrote Pete Chambers, a former U.S. special forces commander and prominent far-right activist, on the social media platform X.
The post received 3.1 million views, yet was only one of several accusations that sprang up around Rainmaker’s activities and its alleged connection to the flood.
“Anyone who calls this out as a conspiracy theory can go F themselves,” wrote Michael Flynn, former national security advisor under the first Trump administration, atop a repost of Chambers’ tweet.
The flurry of allegations was quickly debunked, with a number of independent scientists saying that the company’s actions could not have produced anywhere close to the amount of rain that triggered the flood.
“It’s very clear that they have nothing to do with it,” said Daniel Swain, a climate scientist with the University of California Agriculture and Natural Resources, in a YouTube briefing following the flood.
Rainmaker also denied the claims. The storm dropped as much as four inches of rain per hour over Texas Hill Country, and the river in some places rose by 26 feet in less than 45 minutes.
But in some ways, the damage was done. Conspiracy theorists who have long alleged that Deep State Democrats are controlling the weather now had a real incident to point to. And researchers, companies and experts working to study and perform weather modification and geoengineering practices — which some say will be needed as climate change worsens — now have an even bigger hurdle to overcome.
Within hours of the deadly flood, Republican Rep. Marjorie Taylor Greene said she was introducing a bill to make all forms of weather modification — such as cloud seeding — a felony.
“This is not normal,” the Georgia representative said in a post on X. “No person, company, entity, or government should ever be allowed to modify our weather by any means possible!!”
That same week, the U.S. Environmental Protection Agency launched two new websites to “address public questions and concerns “ about weather modification, geoengineering, and contrails, or the thin clouds that form behind aircraft at high altitudes.
“To anyone who’s ever looked up to the streaks in the sky and asked,’ what the heck is going on?,’ or seen headlines about private actors and even governments looking to blot out the sun in the name of stopping global warming — we’ve endeavored to answer all of your questions,” EPA Administrator Lee Zeldin said in a video accompanying the websites’ launch. “In fact, EPA shares many of the same concerns when it comes to potential threats to human health and the environment.”
The EPA website notes that there is a distinction between geoengineering, which involves a broad range of activities designed to modify global temperatures, and weather modification techniques such as cloud seeding, which are generally short-lived and localized.
In fact, the process of cloud seeding was invented in the United States and has existed for nearly 80 years. General Electric scientists Vincent Schaefer, Irving Langmuir and Bernard Vonnegut — older brother of the late novelist Kurt Vonnegut — began experimenting with it as early as 1946.
On July 2, Rainmaker’s team was working in Runge, Texas, about 125 miles southeast of where the Guadalupe River would soon flood, according to Augustus Doricko, founder and chief executive of the company, which is headquartered in El Segundo.
The team flew its plane to an elevation of 1,600 feet and dispersed about 70 grams of silver iodide into the clouds — an amount smaller than a handful of Skittles, Doricko said. The bright yellow compound is known to latch onto water droplets that are already present in clouds, converting them into ice crystals that can fall as rain or snow, depending on the temperature below.
Soon after the flight, Rainmaker’s meteorologists identified an inflow of moisture to the region and advised the team to suspend operations, which they did, Doricko said. Around 1 a.m. the next day, the National Weather Service issued its first flash flood watch for the Kerr County region.
Doricko said there’s no chance Rainmaker’s actions — which were contracted by the nonprofit South Texas Weather Modification Assn. and on file with the National Oceanic and Atmospheric Administration — contributed to the flood.
“The biggest and best cloud seeding operations we’ve seen to date have produced tens of millions — and maximally like 100 million — gallons of precipitation,” he said. “We saw in excess of a trillion gallons of precipitation from that flood. Not only could cloud seeding not have caused this, but the aerosols that we dispersed days prior could not have persisted in the atmosphere long enough to have had any consequence on the storm.”
Multiple independent experts agreed.
During his briefing, Swain noted that cloud seeding does not create new clouds — it must be conducted on preexisting clouds that already have water vapor or small liquid drops inside of them, essentially enhancing what already had the potential to fall. What’s more, its effects last “minutes to maybe an hour,” Swain said.
“Best-case-scenario estimates — absolute best-case — are that these cloud-seeding operations are able to augment the amount of precipitation by at most 10% to 15% over very limited areas,” Swain said. “On average, it’s a lot lower than that. In fact, in some cases, it’s difficult to prove that cloud seeding does anything at all.”
Indeed, Andrew Dessler, a professor of atmospheric sciences at Texas A&M University, has gone so far as to call cloud seeding a scam — in part because it can prey on farmers and other people who are desperate for rain, and because it typically delivers only modest results, he said.
“There’s no physical way that cloud seeding could have made the Texas storm,” Dessler said, noting that the storm was fueled by extremely high levels of atmospheric water that stemmed from a tropical disturbance in the Gulf of Mexico. “This is a nonsense argument. There’s no debate here about whether cloud seeding played a role in this disaster.”
Dessler said the whole dust-up surrounding Rainmaker and the Texas flood is a distraction from the very real issues and challenges posed by global warming. The amount of material injected into the atmosphere during cloud seeding and geoengineering operations pales in comparison to the trillions of tons of carbon dioxide humans have already spewed into the atmosphere, he said.
“The real irony here is that in some sense, the argument they’re making is correct — there is a conspiracy to change the climate,” Dessler said. “It’s through the emission of carbon dioxide, and it’s by fossil fuel interests and the ecosystem that goes with that. That’s the conspiracy.”
Such limitations haven’t stopped governments and municipalities from investing in cloud-seeding technology.
One of Rainmaker’s first clients was the Utah Department of Natural Resources, which was interested in cloud seeding as a response to the drying of the Great Salt Lake, Doricko said. His company has also contracted with the Colorado Department of Natural Resources, the Oregon Department of Agriculture and multiple municipalities in California, including the Public Works Departments of Santa Barbara and San Luis Obispo counties.
David Spiegel, supervising engineer with San Luis Obispo County’s Public Works Department, said the county first began exploring cloud-seeding technology in the early 2000s in response to severe drought conditions and dwindling supplies at the Lopez Lake reservoir, which feeds five city agencies nearby. It took years to get the program off the ground, and it didn’t ultimately run until 2019 through 2024 — when the state was dealing with yet another drought — to somewhat middling results.
Specifically, San Luis Obispo’s cloud-seeding program added about 1,200 acre-feet of water per year to the nearly 50,000 acre-foot reservoir, he said. (An acre-foot is about 326,000 gallons.) In its best year, it added about 2,500 acre-feet.
Part of the challenge was that there weren’t many clouds in the area to work with, Spiegel said. “We didn’t have enough storms to seed because we were still in this drought period, so it was kind of unfortunate.”
However, he still saw the program as a success because the small water supply gains that came from the cloud seeding priced out to about $300 per acre-foot — far less than the cost of importing supplies from other sources such as the State Water Project, which can run closer to $1,500 an acre-foot. He said he would still consider cloud seeding in the future should the reservoir run low again.
“We definitely see it as a viable option,” Spiegel said.
So far, the state isn’t investing in its own cloud-seeding programs, though it does keep a close eye on them, according to Jason Ince, a spokesman with the California Department of Water Resources. He said any groups conducting cloud seeding work are required to notify the agency by submitting a notice of intent.
An October report published by the department indicates there have been at least 16 cloud-seeding projects across multiple counties and watersheds in California in recent years.
Such efforts could become useful as climate conditions keep moving in the wrong direction: Warming temperatures and overuse are sapping groundwater supplies in California, while state and federal officials are still mired in negotiations over use of the Colorado River — a rapidly shrinking water lifeline that supplies 40 million people across the American West.
Meanwhile, global average temperatures continue to soar driven largely by fossil fuel emissions and human activity. Many experts say there’s a good chance that some form of intervention — weather modification, geoengineering or some altogether new technology — will be needed in the years ahead.
“Weather modification projects are vital resources to enhance fresh water supply for communities within their watersheds,” the Department of Water Resources report says. It recommends that the state continue to support existing cloud-seeding projects in the state and help facilitate new ones.
Speigel, of San Luis Obispo County, said laws banning cloud seeding and other weather modification measures — such as the one posed by Rep. Greene — would be a detriment to the region.
“It would be a setback for us, because we are constantly looking for other opportunities for water,” he said. “It would limit our ability to seek out means of more water in these long drought periods. … I definitely think it would stifle our ability to help our customers.”
Even more controversial than cloud seeding are geoengineering techniques to block the amount of solar energy reaching the Earth. Some involve injecting sulfur into the stratosphere. A 2021 report on geoengineering published by the National Academies of Sciences affirmed that “meeting the challenge of climate change requires a portfolio of options,” but advised caution around such methods.
“(Solar geoengineering) could potentially offer an additional strategy for responding to climate change but is not a substitute for reducing (greenhouse gas) emissions,” the report says.
Dessler, who is also the director of the Texas Center for Extreme Weather at Texas A&M, likened geoengineering to airbags on a car — something no one ever hopes to use but that would be good to have in a climate emergency.
He said the focus should continue to be on reducing the use of fossil fuels, and that the talk of banning geoengineering, cloud seeding and other forms of weather modification by members of the Trump administration and some lawmakers is more political than scientific.
“It makes no sense — it shows you that this is not an argument about facts. It’s an argument about worldview,” he said.
The president has taken many steps to undo efforts to address climate change in recent months, including withdrawing from the Paris climate accord, an agreement among some 200 nations to limit global warming to under 2 degrees Celsius (3.6 degrees Fahrenheit).
The EPA has also removed several barriers and regulations that govern oil and gas drilling in the U.S., and has said it wants to repeal the endangerment finding — a long-held legal and scientific determination that CO2 emissions harm human health and welfare, among other significant changes.
Doricko, Rainmaker’s CEO, said he was disappointed to see cloud seeding politicized in the wake of the Texas flood. He was taken aback when he saw that Rep. Greene had posted a picture of his face on X — “insinuating somewhat that cloud seeding, or I, was responsible for the natural disaster in Texas, when any meteorologist or atmospheric scientist could tell you otherwise,” he said.
“Human civilization is unintentionally modifying the weather and the climate all the time,” Doricko said, including through fossil fuel emissions and urban heat islands that warm surrounding areas. “What Rainmaker is trying to do is bring some intentionality to that, so that we can modify the weather for our benefit and deliberately.”
Doricko said he is also an advocate of more transparent reporting, more stringent regulations, and whatever else is needed to build trust with the public about “a really consequential technology.”
He said he will continue to engage with skeptics of the technology in good faith.
“Cloud seeding is a water supply tool, and whether you’re a farmer in a red state or an environmentalist in a blue state, water is as nonpartisan as it gets,” he said. “Everybody needs water.”
