Dotting the Wasatch, Uinta, and La Sal mountain ranges in Utah stand 190 remote-controlled, cloud-seeding generators—the largest system of its kind in the world. Persistent aridification throughout the Southwest compelled Colorado Basin states, like Utah, to increase their budgets for cloud seeding. At the same time, states like Florida and Tennessee codified bans on all weather modification. Doubts about its efficacy, potential side effects, and conspiracy theories prompt questions of whether regional or national governance will provide the best regulatory framework for cloud seeding’s future.
The Science
Neither a fringe technology nor a recent invention, cloud seeding’s discovery took place in 1946 at the General Electric Research Laboratory in Schenectady, New York. There, chemists Vincent Schaefer and Nobel laureate Irving Langmuir showed that dry ice dropped into a cold cloud could cause ice crystal formation and snowfall. Soon after, Bernard Vonnegut found that silver iodide produced the same effect at warmer temperatures and much lower concentrations. Silver iodide remains the main cloud seeding agent ever since. More recently, countries like the United Arab Emirates tested hygroscopic flares containing natural salts such as potassium chloride, sodium chloride, and magnesium chloride to increase rainfall at higher temperatures.
In Utah, between November and April, remote-controlled generators pump silver iodide (molecularly similar to salt) into storm clouds to coax more precipitation. Silver iodide provides sub-freezing water droplets with a nucleus on which to freeze and fall as snow or rain. Silver iodide does not create snow out of thin air. After the Great Salt Lake dropped to record low levels in 2022, Utah’s legislature expanded its cloud-seeding budget from $200,000 to $16 million, with a $5 million per year recurring allotment. Utah looks to further expand its seeding program by replacing airplanes with drones for more precise delivery, flying directly into the clouds where temperatures are optimal for ice nucleation.
Skeptics have long voiced doubts about cloud seeding’s effectiveness in mitigating aridification caused by climate change. Until SNOWIE (Seeded and Natural Orographic Wintertime clouds: the Idaho Experiment), a groundbreaking 2017 study that demonstrated clear precipitation enhancement. Scientists, policymakers, and even beneficiaries debated its efficacy. As late as 2003, the National Research Council report stated that science could not confirm significant seeding effects with high confidence. SNOWIE moved the needle. Studies from Utah’s own operational programs now estimate precipitation increases of three to thirteen percent in seeded areas. At a cost of $5 to $10 per acre-foot, cloud seeding is extremely cost-effective compared to other water supply strategies. For example, Utah's Demand Management Pilot Program pays farmers $390 per acre-foot not to irrigate, and desalination costs in California exceed $3,000 per acre-foot. Currently active improvements to cloud seeding exist. A recent report to the Utah’s Division of Water Board indicated that cloud seeding increased the state’s snowpack by 10.4%, or 200,000 acre-feet, enough water to supply over 400,000 homes.
Regional collaboration
Because snowpack remains Utah’s largest reservoir, and more runoff means fuller downstream flows, the Colorado River Basin states of Arizona, California, and Nevada each contribute $500,000 to Utah’s cloud-seeding program. Idaho separately invested $1 million in Utah's cloud seeding operations focused on the Bear River watershed, a system that serves both states. These cross-border funding arrangements reveal an important fact about how cloud seeding functions in practice: it is inherently regional, tied to watersheds and river systems that do not respect state lines.
A Nation Divided
While Western states with starkly different politics unify under a cloud-seeding umbrella, a very different legislative story is unfolding in state capitals across the rest of the country. In 2024, Tennessee became the first state in the nation to pass a law banning cloud seeding and other weather modification activities. Florida followed in 2025 by passing a sweeping geoengineering prohibition that took effect July 1, 2025—classifying unauthorized weather modification as a felony punishable by up to five years in prison and fines of up to $100,000. Montana took a narrower approach, passing Senate Bill 473, which bans broad geoengineering practices but explicitly carves out cloud seeding for water resource management. Similar legislation was introduced in 2025 in Rhode Island, Pennsylvania, North Carolina, and Texas, among others. In early 2026, Iowa’s House passed a cloud-seeding prohibition.
This legislative wave reflects a divergence in states’ political zeitgeist concerning weather modification projects. In the arid West, where ninety-five percent of Utah's water supply depends on seasonal snowmelt and ranchers, ski resorts, and hydroelectric utilities all possess a direct financial stake in snowpack levels, cloud seeding provides a practical tool in an increasingly desperate water-management toolkit. In states like Florida and Tennessee, where cloud seeding has not been practiced in decades—Florida’s program ended roughly fifty years ago—the legislation appears rooted less in water policy than in a political reaction to conspiracy theories about chemtrails and government weather control that circulated widely after Hurricanes Helene and Milton in 2024. This current divergence makes national consensus on cloud seeding policy seem virtually impossible.
Litigation, Liability, and the Causation Problem
Cloud seeding’s litigation history in the United States is almost as old as cloud seeding itself and defined predominantly by the need to prove causation. The first weather modification lawsuit links to the 1916 California case of Hatfield v. City of San Diego, in which rainmaker Charles Hatfield contracted with the city to fill the Morena Reservoir; subsequent flooding triggered a wave of claims that ultimately settled without establishing legal precedent. In Slutsky v. City of New York, a resort owner sought an injunction, but the court denied it, holding that private parties hold no vested property rights in clouds or the moisture therein. Cases arising from seeding operations in Oklahoma and Michigan in the early 1970s—Samples v. Irving P. Krick, Inc. and Reinbold v. Sumner Farmers, Inc.—saw juries find that plaintiffs could not prove cloud seeding caused the flood damage they claimed. Absolute immunity for the federal government, based on the Flood Control Act of 1929, connected to cloud-seeding in Lunsford v United States after a 1972 flash flood in South Dakota caused property damage and over 200 deaths. Plaintiffs filed suit alleging that, prior to the flood, a contractor working for the Bureau of Reclamation of the US Department of the Interior, acted negligently while operating under threatening weather conditions. The pattern remains with remarkable consistency: even where a seeding operation can be established as a fact, connecting it to specific downstream harm has proven difficult, if not impossible, to demonstrate under standard tort causation frameworks.
Federal versus State Regulatory Power
In a Syracuse Law Review article, scholars Michael Conklin and Justin Robert Blount argue that the non-existent federal regulation over cloud-seeding, combined with the causation issues that make tort litigation ineffective, creates a legal vacuum that disproportionately harms disadvantaged communities. Manon Simon, in Enhancing the Weather: Governance of Weather Modification Activities in the United States, compares cloud-seeding regulation in California and Texas and concludes that weather modification laws across the states remain fragmented and inconsistent. The National Oceanic and Atmospheric Administration (“NOAA”) enforces the 1976 National Weather Modification Policy Act mainly by monitoring operations through required reporting of cloud-seeding operations and imposing fines of up to $10,000 for reporting failures. The case for federal regulation argues a straightforward idea: clouds do not recognize state borders. For example, a Wyoming cloud-seeding operation can deprive a Colorado watershed of precipitation that would otherwise fall there.
Yet the past two years of state legislative activity suggest that governance at a national level might not be the best solution. Perhaps, the wildly divergent legislative responses to cloud seeding across American state capitals reflect not a regulatory failure but a feature of a functioning federal system. That is, states with disparate geographies, water needs, and political cultures reach disparate conclusions about the same technology. Utah and its neighbors in the Colorado River Basin expand cloud seeding programs because their survival depends on snowpack. Tennessee and Florida banned it because their electorates, shaped by different anxieties and different weather realities, demanded prohibition. Montana threaded the needle by banning stratospheric geoengineering while protecting cloud seeding in water management programs. Montana remains the only state that requires all weather modification operations to attain an Environmental Impact Assessment (“EIA”). These are not irrational positions. They are local judgments made by local governments in response to local conditions. Professor of Water Law at Arizona State, Rhett Larson, in his book Just Add Water, suggests that “the water-security paradigm should not be led by hierarchists, entrepreneurs, or ethicists. It should be led by regionalists.” Unlike issues such as carbon emissions and global climate change, the regionalist governance of water security keeps decision-making in the hands of those most familiar with the “unique climate, geology, hydrology, economy, and culture of water.”
Utah illustrates this principle. The disastrous environmental implications of the drying of the Great Salt Lake, as well as possible reductions in Colorado River allocations, prompted the state legislature to take immediate action to channel more funding toward water management, including cloud seeding and research. The 2026 SNOWSCAPE initiative (Seeded and Natural Orographic Winter Storms Catchment Processes and Evaluation) is a collaborative research program that collects high-resolution data on key variables in cloud seeding to calibrate two highly specific measurement models. The project includes scientists from the University of Utah, the National Center for Atmospheric Research, and Utah State University. In addition, Utah launched a comprehensive trace-chemistry study to analyze snowmelt, stream water, lakebed sediments, and soils to detect silver at concentrations as low as parts per trillion. Appropriately, these innovative efforts to raise water levels throughout Utah without endangering the environment created by lawmakers and researchers best positioned to understand the State’s unique challenges.
References
- Ben Winslow, Utah Now Runs the World’s Largest Remote-Controlled Cloud Seeding Program, FOX 13 NEWS (Oct. 9, 2025), https://www.fox13now.com/news/colorado-river-collaborative/utah-now-runs-the-worlds-largest-remote-controlled-cloud-seeding-program#google_vignette (last visited Mar. 24, 2026).
- Sarah A. Tessendorf et al., A Transformational Approach to Winter Orographic Weather Modification Research: The SNOWIE Project, 100 Bull. Am. Meteorological Soc'y 71 (2019), https://doi.org/10.1175/BAMS-D-17-0152.1.
- Nat'l Research Council, Critical Issues in Weather Modification Research (2003), https://doi.org/10.17226/10829.
- U.S. Gov't Accountability Off., Cloud Seeding Technology: Assessing Effectiveness and Other Challenges, GAO-25-107328 (Dec. 19, 2024), https://www.gao.gov/products/gao-25-107328.
- Michael Conklin & Justin Robert Blount, Bad Policy Runs Downhill: How Cloud Seeding Jurisprudence Disproportionately Harms Disadvantaged Communities, 75 Syracuse L. Rev. 1 (2025), https://papers.ssrn.com/sol3/papers.cfm?abstract_id=4851009.
- Manon Simon, Enhancing the Weather: Governance of Weather Modification Activities in the United States, 46 Wm. & Mary Envtl. L. & Pol'y Rev. 149 (2021), https://scholarship.law.wm.edu/wmelpr/vol46/iss1/5.
- Margaret Manto & Addy Baird, National Political Scrutiny of Cloud Seeding Looms Over Utah, Undark Mag. (Nov. 17, 2025), https://undark.org/2025/11/17/geoengineering-scrutiny-utah.
- Rhett Larson, Just Add Water: Solving the World's Problems Using Its Most Precious Resource (2020), https://global.oup.com/academic/product/just-add-water-9780190948009.
- Utah Div. of Water Res., SNOWSCAPE 2026, https://water.utah.gov/snowscape/ (last visited Mar. 24, 2026).



