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- Utah is exploring drone-based cloud seeding to boost precipitation, marking a new innovation.
- The state has increased its cloud seeding budget significantly in recent years.
- Drones are seen as cheaper, safer and a more precise alternatives to other operations.
SALT LAKE CITY — Utah has experimented with cloud seeding for decades, using ground devices and airplanes to disperse silver iodide and liquid propane to pad moisture statistics in one of the nation's driest states.
These efforts have helped boost precipitation by about 6% to 12% over the past 30 years, Jonathan Jennings, meteorologist and cloud seeding coordinator for the Utah Division of Water Resources, explained to lawmakers and others gathered outside the state Capitol Thursday.
"(It) might not seem like a lot, but when you cover the entire state of Utah and then expand it over a decade, that's an additional half-year to a year of precipitation," he said, adding that it's produced as much as 200,000 acre-feet of additional water flowing in Utah's streams.
The future of cloud seeding may come in the form of a different type of aircraft, too. Utah water managers — in coordination with Utah State University — tested drone-based cloud seeding during a storm that passed through the Cache Valley last weekend, marking a new first in its use.
It's part of a program that seeks "innovative" ways to perform cloud seeding after state lawmakers boosted its annual cloud seeding budget from $300,000 to $5 million in recent years, Jennings said. The division is also seeking $2 million in one-time funding and $700,000 in ongoing funding from the Utah Legislature this year as it explores "advanced" operating within the Bear River Basin with neighboring states.
The growth of cloud seeding
About 95% of Utah's water supply comes from the snowpack collection and spring snowmelt process. Utah began exploring cloud seeding in the 1950s — a few years after the concept was first introduced — to help boost its water bounty.
Its current program was created in 1973. Utah water managers explain that planes disperse silver iodide into clouds because its structure is similar to an ice crystal, mixing in the clouds to help ensure that moisture in them precipitates down. Ground devices, on the other hand, send emissions from liquid propane into the air, which creates "intense evaporative cooling" and a better opportunity for snow.
These tactics are typically deployed across mountain ranges when colder, moisture-heavy systems move through the state, Jennings explained.
Combined, these efforts have been "effective" across the state's mountain ranges, the Utah Division of Water Resources says. It's why Utah and many other Western states have expanded their use, especially since the two-decade-long "megadrought" impacted water supplies throughout the region.
However, researchers say it does have limitations. A 2016 study led by researchers in Spain cautioned that cloud seeding may affect land and water ecosystems if it is "repeatedly applied in a specific area" or large amounts of silver iodide are released at once.
There are other issues associated with cloud seeding, Laura Kurl, an associate professor at Northeastern University, wrote in a 2022 piece for the Bulletin of the Atomic Scientists. These include unknowns tied to weather modification and mixed results when it comes to benefits.
Jennings contends the state's 6% to 12% boost is proof that efforts are working, adding that the state will conduct its own environmental review, but levels of silver iodine released are well below federal standards.
"For how long we've been doing this program, if there were negative effects, we'd be feeling them by now," he said.
A new form of cloud seeding
This winter's conditions have made it difficult to conduct cloud seeding in central and southern Utah as compared to previous winters. State officials believe efforts in the Bear River Basin could have positive impacts there, including getting water to the Great Salt Lake.
This year's appropriations request would be part of a possible multistate agreement with Idaho and Wyoming, which seeks to be the first multistate cloud seeding agreement of its kind.
Cloud seeding is also on the cusp of relying on new technology. Utah water managers displayed the drones they started testing along with Sandy-based North American Weather Consultants in the Cache Valley.
Each drone disperses a powdered form of silver iodide as compared to a burning solution that planes release. Jared Smith, general manager of North American Weather Consultants, said it offers a way to fly above inversions that hinder ground operations while it's cheaper, safer and more precise than flying planes into cold storms.
"This is the first operational program in the U.S. with drones — it's very new," he told KSL.com.
Given its newness, it took research and development to make sure each drone could handle icing and other challenges. Drone cloud seeding is also "purely experimental," at this point, and confined to the Cache Valley because — with the help of USU — it's the only area with Federal Aviation Administration clearance, Jennings adds.
Its expansion to other Utah regions is unclear, as it's dependent on future FAA approval.
Drones could add to the growing cloud seeding operations in the state. Candice Hasenyager, director of the Utah Division of Water Resources, said the division is planning to nearly double the number of remote ground generator devices it has to deploy across the state.
"These are really beneficial because we can put them in remote locations that can help us maximize our cloud seeding efforts," she said.
