Getting the Facts on Cloud Seeding
Evidence-Based Information on a Widely Misunderstood Technology
Cloud seeding is one of the most widely studied, yet misunderstood, weather modification techniques. It has been used around the world for decades to enhance precipitation, support agriculture, and manage water resources. This site provides clear, science-based answers about what cloud seeding is—and isn’t.
History of Cloud Seeding
Cloud seeding has been around since 1946, when scientists at General Electric, including Nobel laureate Irving Langmuir, first experimented with using silver iodide and dry ice to stimulate precipitation. Since then, it has been studied, regulated, and deployed in over 50 countries for water management. Cloud seeding in the U.S. dates back more than 75 years, with robust state-run programs in places like Colorado, Utah, and Nevada. Over time, the technology has evolved alongside weather models, aircraft technology, radar systems, and environmental monitoring tools that help track cloud development and measure precipitation.
How It Works
The Basics of Cloud Seeding
Cloud seeding introduces small particles, typically silver iodide or salt-based materials, into clouds to encourage the formation of ice crystals, which can then grow and fall as rain or snow. These particles act as cloud condensation or ice nuclei, similar to the dust or sea salt already present in the atmosphere which naturally stimulate the precipitation process. Importantly, cloud seeding only works when the atmosphere already contains cold, moisture-rich clouds—conditions that are already capable of producing precipitation on their own. Cloud seeding enhances these natural processes; it cannot create clouds or weather systems from scratch.
Benefits & Limitations
BENEFITS:
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Increased snowfall or rainfall in water-stressed areas
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Support for agriculture and wildfire mitigation
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Non-invasive and significantly lower cost than infrastructure alternatives
LIMITATIONS:
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Only effective under specific meteorological conditions
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Cannot “make” storms or shift weather systems on a large scale
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Effectiveness is limited by various atmospheric variables
The SNOWIE campaign of 2019, led by the National Center for Atmospheric Research (NCAR), was the first to directly measure the results of cloud seeding using advanced radar and aircraft sensors. It confirmed measurable snowfall increases attributable to cloud seeding in real time.
International Activity
Countries around the world—including China, India, Australia, and the UAE—use cloud seeding programs to enhance water security and combat drought. China in particular has invested heavily in weather modification infrastructure, especially around major events like the 2008 Olympics and for agricultural support in arid regions. The country spends $1.4 billion on cloud seeding every year while employing over 35,000 people in the state-run weather modification office. International programs vary widely in transparency, regulatory oversight, and scientific rigor. The U.S. approach remains rooted in environmental safeguards, peer-reviewed research, and public accountability.
Safety and Regulation
Cloud seeding in the U.S. is regulated at both the state and federal levels, with oversight from agencies like the Environmental Protection Agency (EPA) and the National Oceanic and Atmospheric Administration (NOAA). The EPA has issued guidance on geoengineering and weather modification, recognizing cloud seeding as a distinct, localized, and low-impact practice.
Multiple peer-reviewed studies, including over 30 years of data on soil and water samples, have shown that silver iodide concentrations in snow and downstream water are orders of magnitude lower than EPA safety thresholds.
Frequently Asked Questions