Nevada looks to cloud seeding amid record low snowpack
Jeniffer Solis
(Nevada Current) Monitoring stations across Nevada continue to measure record low snowpack this winter as high temperatures and dry weather hamper snow accumulation, testing one of the state’s only tools to create more.
Since 2023, the Nevada Legislature has provided the Desert Research Institute with an annual budget of $600,000, reviving state support for a long-running cloud seeding program that promises to boost snowfall in the driest state in the union.
The program covers four mountain ranges: Tahoe-Truckee in Washoe County, Santa Rosa in Humboldt County, Ruby Mountains in Elko County, and Spring Mountains in Clark and Nye Counties.
Water in Nevada is primarily provided by mountain snowfall during winter storms which help create natural reservoirs that provide a steady stream of spring runoff for cities, agriculture, and natural habitats during warmer drier months. But periodic drought and competing water needs are often greater than what’s produced by nature.
Nevada’s cloud seeding program isn’t new. The program operated for more than three decades before the Great Recession eliminated state funding in 2009. In the following years, the Southern Nevada Water Authority, the Truckee Meadows Water Authority, and the Humboldt River Basin Water Authority provided some funding to support the program, but it wasn’t enough to keep operations running on a large consistent scale.
“Local water districts would come to the table when there were drought conditions, but then as soon as it got wet, they wanted to allocate the resources to other things, and the seeding program would disappear,” said Frank McDonough, the director of Nevada’s cloud seeding program at the Desert Research Institute.
Several developments helped change the course on state funding for the program.
Drought conditions across the West reached dire levels in August 2021 when, for the first time in history, the U.S. federal government declared a formal water shortage for the Colorado River, triggering mandatory cuts in water delivery to Nevada and other lower basin states the following year.
Drought across the rest of Nevada during the 2021-2022 winter was equally grim. That winter snowpack in Nevada only reached about 75% of historic average, according to the U.S. Drought Monitor.
In response, the Humboldt River Basin Water Authority turned to cloud seeding to bring additional water to the drought-striken basin, securing $120,000 in private grant funding to cloud seed in the Ruby and Santa Rosa Mountains, producing an estimated nearly 5,000 acre-feet of snow water equivalent.
After the dismal winter snowpack, natural reservoirs in Nevada in 2022 remained well below average capacity, including Lake Tahoe, Lahontan, and Rye Patch, according to the Nevada Division of Water Resources. The Humboldt River also experienced record low flows that summer.
Nature provided a reprieve from the ongoing drought in the winter of 2022-2023, when snowpack in Nevada reached record levels in Tahoe-Truckee and the Ruby Mountains. The following winter, the first winter DRI performed cloud seeding under the revived program, was also a strong year for winter storms, giving researchers plenty of opportunities to cloud seed under ideal conditions.
From November 2023 to April 2024, Nevada’s cloud seeding operations produced snow equivalent to 56,282 acre-feet of water – enough to serve 140,000 Nevada homes at a cost of $10.66 per acre foot, according to DRI.
Nevada’s second winter relaunching the program with state funding was also strong, but there were less storms and clouds compared to the previous year for researchers to seed, reducing what could be pulled from the clouds.
DRI estimates their operations during the 2024-2025 winter produced snow equivalent to 40,674 acre-feet of snow water equivalent, enough water for the yearly use of over 100,000 Nevada homes at a cost to the state of $14.75 per acre-foot.
This winter is proving to be a challenging year for Nevada. Snowpack in the State of Nevada and Eastern Sierra in California is well below normal at 56% of median, compared to 94% at this time last year.
Snow monitoring stations across Northern Nevada have recorded the lowest snowpack since 1981 this winter, according to forecasters at the National Resource Conservation Service.
McDonough, the director of Nevada’s cloud seeding program at the Desert Research Institute, says that means every acre foot equivalent of snow pulled will be vital.
“Cloud seeding is really the only opportunity to really increase water resources, and it’s done at about $10 an acre foot,” McDonough said.
“You can get somewhere on the order of 10 to 15% more snow within the cloud seeding area. It’s a decent amount of precipitation, especially for a state like Nevada, where our snow pack is critical to our water supplies,” he continued
Researchers at DRI won’t know the full details about this year’s cloud seeding until they review data in April, but conditions haven’t been ideal, said McDonough.
“This is a lean year so far,” he continued.
Silver iodide and a propane flame
Cloud seeding can only be done in very specific conditions. Winter storms can only be seeded when widespread low clouds move over the project areas. Clouds also need to come in from a certain direction and at no higher than 23 degrees Fahrenheit.
“If they don’t have the sub freezing water drops, there’s no opportunity to grow snow. We need the wind directions to be from the proper direction where the cloud seeding generators are going to be able to release into the clouds,” McDonough said.
Cloud seeding is a safe and proven method to increase the efficiency of clouds to produce additional snowfall. A microscopic amount of silver iodide is released across a propane flame, which then rises into the clouds and enhances a cloud’s ability to convert super-cooled liquid droplets into ice crystals. Those ice crystals grow big enough to fall as increased snow in targeted areas.
Silver iodide is a naturally occurring inorganic molecule with a structure very similar to ice, that similarity attracts ice formation around the molecule to the point where snow can form.
The Nevada state program is conducted from the ground through strategically placed generators which only operate when cloud seeding conditions are met.
Surrounding states have invested much more funding into cloud seeding. Utah spends $9.2 million per year on cloud seeding, and receives some additional funding from water providers in California, the Southern Nevada Water Authority, and the Central Arizona Project.
Wyoming spends $800,000 per year on cloud seeding programs, plus additional funding from Lower Basin states. Idaho spends $4 million per year on cloud seeding programs, and Colorado spends $700,000 per year on cloud seeding programs, with additional funding from lower basin states.
Electric utilities such as Idaho Power and Southern California Edison have also used it to help fill reservoirs, making hydropower more efficient.
In recent years, the federal government has also responded to severe drought through cloud seeding efforts. In 2023, the Bureau of Reclamation provided a $2.4 million grant to the Southern Nevada Water Authority for cloud seeding operations in Colorado, Utah, and Wyoming aiming to increase water supply in Lake Mead.
While states and the federal government have invested in cloud seeding, there are gaps in the research on how effective cloud seeding is, according to the Government Accountability Office.
The amount of precipitation that would have occurred in the absence of cloud seeding— known as “baseline” precipitation—is difficult
to determine with certainty.
“It’s not that easy to prove because of the natural variability inside storms,” McDonough said. “You can say, ‘all right, the last four years we had more snow in the cloud seeding part of the Tahoe-Truckee than outside of that’ but if you’re a skeptic that’s not enough.”
Still, measurements are more precise now than when the proof of concept for cloud seeding was first discovered in 1946. Over the past few decades, computer model and radar and sensor technology advances have improved evaluations of cloud processes and may help improve understanding of cloud seeding effects.In 2020, a study published in the Proceedings of the National Academy of Sciences used advanced radar and cloud-measuring technology to show that cloud-seeding from three reviewed cases produced enough snow to fill 282 Olympic-sized swimming pools over approximately two hours.