As drought conditions worsen across the American West, a start-up is making waves with its bold claims of cloud-seeding success using drones, raising hope of water relief for desperate communities.
Image: Simon Hurry / Unsplash
Jake Spring
Scientists have been shooting particles into clouds since the 1940s, praying it will bring more rain and snow.
While researchers agree that “cloud seeding” can work in a laboratory setting, many have doubted how much precipitation it can generate in the real world. But that hasn’t stopped Western states in the U.S. from blasting silver iodide into the sky for decades, hoping it will relieve harsh droughts.
Now, start-up company Rainmaker said it has proved its cloud-seeding drones produced 142 million gallons of water in the form of snow. Some scientists said it’s too soon to know if the results are legitimate, as the data has yet to be peer reviewed, and even then it is a small amount of water in the face of the West’s intense drought. But, if confirmed, it could be a breakthrough, making it the first commercial cloud-seeding operation to prove it made precipitation.
Utah and Idaho are already paying the company millions of dollars a year in a bid to relieve the drought hitting farmers and cities in the basin that runs into the rapidly shrinking Great Salt Lake.
“We’re looking at a really, really kind of dire situation, drastic times and we’ve got to be smart with the water we have,” said Joel Ferry, executive director of the Utah Department of Natural Resources. “We can’t be stuck in kind of the old ways. And a big part of that is using cloud seeding.”
Rainmaker is doing “a lot of really cool stuff,” said Katja Friedrich, a cloud microphysics expert and professor at the University of Colorado Boulder, including being the first U.S. company to use drones to seed clouds.
Rainmaker’s method uses techniques already employed by Friedrich and a group of other academics, who were the first to use physical observations to prove cloud seeding works in a 2019 paper. But she emphasised the need for their results to be peer-reviewed. The company has said it will pursue peer review, which could take more than a year.
“If they want to be credible, they have to go through this, because otherwise it’s just numbers on a piece of paper,” said Friedrich, who is not involved in Rainmaker, although the company has hired one of her former doctoral students.
Cloud seeding appeals to states eager to increase the snowpack that the West overwhelmingly relies on for water, said Augustus Doricko, the 26-year-old founder of Rainmaker, in an interview.
“Making more snow for the farms and for the ecosystems and for those ski resorts and utilities that need it is something that concerns every demographic, every person across the American West where water is scarce,” Doricko said.
Rainmaker is currently the only U.S. company actively using drones rather than airplanes to cloud seed, a move the company says will cut costs and allow for more frequent, widespread and precise flights. The drones release silver iodide that causes liquid in the clouds to turn into ice and ultimately fall to the ground as snow.
The drones also do not require putting pilots at risk who would otherwise have to fly in some of the worst conditions in icy clouds. The silver iodide will only work in clouds cooled to at least minus-5 degrees Celsius.
“If we’re using our manned research aircraft, they often have to get out of the cloud because they ice up,” Friedrich said. “So it’s not really a nice Sunday afternoon flight.”
That’s how Western states have been doing it for decades. Then Utah scrapped its planes last year, part of an effort to scale up cloud seeding operations and shift to drones.
The state’s annual cloud seeding budget is now $7 million (R116 million), up from about $350,000 five years ago, when an intense drought spurred the state to take more action to conserve and increase its water resources, Ferry said.
The Great Salt Lake itself embodies the state’s urgent water shortage. The lake has been declining since 1986, with its surface area shrinking to a nearly a quarter of that peak, said David Tarboton, a hydrologist and professor at the Utah Water Research Laboratory at Utah State University. Water usage is the main factor, with people in the area using about half of the water that would naturally flow into the lake, he said.
Rising temperatures are also causing more evaporation directly from the lake, which leads to greater irrigation demands for parched crops, Tarboton said. That also contributes to extremes, including droughts, that increases the natural variability of the lake.
The huge area of newly exposed lake bed has dried out into dust full of arsenic and other carcinogenic metals and that billows into neighborhoods in Salt Lake City. The lower the lake, the saltier it gets, harming the brine shrimp that live there and the birds that feed on them, Tarboton said.
He calculates the lake needs additional inflows of at least 250,000 acre-feet of water - enough to meet the needs of more than half a million Utah households - to help stabilise the lake, with over 800,000 acre-feet needed annually to recover the lake to the levels seen decades ago.
Rainmaker’s efforts to cloud seed so far this year in the Bear River Basin, the main source of the lake’s inflows, resulted in at least 50,000 acre-feet of additional moisture, Ferry said.
Those preliminary numbers are based on a statistical estimate, rather than physical proof that the cloud seeding is actually making snow. Rainmaker said it could only unambiguously prove the creation of 437 acre-feet through its operations so far, with only 30 acre-feet in the basin.
While that amounts to 10 million gallons - a lot for a human - it’s not much for the lake.
“Every little bit helps, but it does seem like it’s quite a small number if it’s correct,” Tarboton said.
Doricko said it’s only a start. The company aims to close the gap between the statistical estimates and what they can physically prove.
Beyond the drones, what sets the company apart from traditional cloud seeding companies is its use of its validation method that is inspired by the SNOWIE project, a collaboration between the National Center for Atmospheric Research and at least three American universities.
That academic project, which published results starting in 2019, was the first to prove by physical evidence that cloud seeding worked, matching up radar signatures with other data. Chinese researchers and Swiss University ETH-Zurich later reached similar results. Rainmaker says it is the first commercial company to do it.
“The methods are sort of state-of-the-art science approaches in terms of looking at radar and looking for unambiguous seating signatures,” said Kara Lamb, an atmospheric physicist and associate research scientist at Columbia University.
Even more so than the Western U.S., China embraced cloud seeding decades ago with tens of thousands of workers in government weather modification offices around the country. Ahead of hosting the Winter Olympics, China shot hundreds of silver iodide shells into clouds with an aim of boosting snow.
Lamb and Friedrich said Rainmaker’s validation could be stronger if matched with precipitation gauges or measurements of stream inflows or groundwater, to show whether the moisture is reaching the ground.
The more evidence that cloud seeding is creating water, Lamb said, the better the case to invest in it.
Ferry, Doricko and Lamb agree, no matter how effective, cloud seeding is not a silver bullet to resolve the West’s water problems. Jonathan Jennings, a meteorologist with Utah’s Division of Water Resources, said that even in a good year, cloud seeding can likely only boost precipitation by 15 percent.
“It is exciting that they’re revisiting this challenge of weather modification with new tools and new techniques,” Lamb said. “But I think there is still the fundamental issues with how effective can weather modification ever be on a large scale.”