- A new study found 71 radar-observed cloud seeding responses during the 2025–2026 winter season.
- Researchers used drones to release silver iodide into cold clouds over Oregon, Idaho and Utah.
- Radar detected changes in precipitation an average of 18 minutes after seeding.
- Researchers estimated 430.44 acre-feet of precipitation associated with the observed changes.
- The study did not establish how much of that precipitation reached the ground.
Tuesday, November 10, 2026 — A California cloud seeding company has published new research showing that drones can produce repeated, measurable changes in precipitation inside winter clouds.
Rainmaker Technology Corporation announced the findings
on November 9, 2026, after publishing its peer-reviewed study in the scientific journal Atmosphere on November 5.
The research examined cloud seeding operations conducted during the winter of 2025–2026 in Oregon, Idaho, and Utah. Using weather radar and other observations, researchers identified 71 precipitation patterns that they attributed to cloud seeding.
The findings provide evidence that the company’s drone-based operations can produce measurable changes inside clouds. However, the researchers cautioned that the study did not determine how much additional snow or rain actually reached the ground.
How Does Cloud Seeding Work?
Cloud seeding is a method of encouraging precipitation from clouds that already contain moisture.
Rainmaker uses drones equipped with special flares containing silver iodide, a substance that helps ice crystals form in cold clouds.
When the drones release silver iodide into clouds containing tiny droplets of water below freezing, the particles can encourage ice crystals to develop.
Under favorable conditions, those crystals grow large enough to fall as snow or other precipitation.
The process depends on having suitable clouds, moisture and temperatures. Cloud seeding does not create moisture where none exists.
Rainmaker’s drones can hover or make short flights within clouds while releasing the seeding material. The aircraft also carry instruments that measure temperature, humidity and atmospheric pressure.
What Researchers Found.
During the 2025–2026 winter season, Rainmaker conducted 484 drone flights involving cloud seeding across three operating regions.
The operations included areas near Pendleton, Oregon; the Bear River Basin in southeastern Idaho; and mountain watersheds in Utah.
Researchers examined radar observations and identified 71 precipitation patterns across 15 periods of intensive observation that met their standards for attributing the changes to cloud seeding.
The radar patterns appeared after silver iodide was released, developed in the expected locations and moved with the wind.
According to the study, the typical sequence was:
-
18 minutes: The first precipitation changes became visible on radar.
-
33 minutes: Radar detected the strongest precipitation signal.
-
36 minutes: The estimated precipitation rate reached its highest level.
-
42 minutes: The affected area reached its greatest size.
-
51 minutes: The typical period during which the precipitation pattern remained detectable by radar.
These measurements represent the middle value, or median, of the observations rather than the timing of every individual event.
The repeated patterns gave researchers evidence that the changes were associated with cloud-seeding operations rather than ordinary weather activity.
Oregon Operations Provided Some of the Clearest Evidence.
One of the strongest examples occurred near Pendleton, Oregon, on January 23, 2026.
During that operation, drones released silver iodide into clouds that were producing little natural precipitation detectable by radar.
The researchers divided 10 drone releases into four groups.
Each group was followed by a new precipitation pattern visible on radar. The patterns developed downwind from the release locations, expanded and moved downward through the atmosphere.
The sequence repeated four times over approximately three and a half hours.
Comparable radar patterns were not present before the seeding operations and did not independently develop elsewhere in the immediate operating area.
Researchers also used satellite images and ground observations to support their findings.
The study identified this operation as particularly useful because the lack of surrounding natural precipitation made the changes easier to distinguish.
How Much Additional Precipitation Was Detected?
Researchers estimated that the 71 observed precipitation patterns were associated with a combined 430.44 acre-feet of water equivalent.
An acre-foot is the amount of water needed to cover one acre of land one foot deep.
The estimate represents precipitation detected by radar and expressed as the equivalent amount of liquid water.
However, the 430.44 acre-feet figure does not represent a confirmed amount of additional water delivered to the ground.
The researchers used 27 different calculations to estimate snowfall from radar measurements. They also examined how changes in their calculations affected the results.
Radar measured about two-thirds of the estimated precipitation volume more than 0.6 miles above the ground.
Some of that precipitation could have evaporated, changed directly from ice into water vapor or drifted before reaching the surface.
The study did not have precipitation gauges beneath the observed patterns to confirm how much fell to the ground.
Researchers also emphasized that the findings do not show how often any individual cloud-seeding flight will produce a detectable response.
Differences in radar coverage and natural precipitation made it difficult to compare every flight under the same conditions.
Rainmaker Plans to Expand Operations.
Rainmaker, based in El Segundo, California, currently operates in Utah, Idaho, Oregon, California and Colorado.
The company said the published findings support its approach to using drones and radar to measure cloud seeding results.
Rainmaker founder and Chief Executive Officer Augustus Doricko described the publication as part of the company’s commitment to scientific research.
“As we continue to advance the science of cloud seeding, we will operate as a research-driven company working at the forefront of science to validate our results and deliver new water for our customers,” Doricko said in the November 9 announcement.
The company also expects its internal cost of producing water through cloud seeding to decline as operations expand.
According to its announcement, Rainmaker expects its cost per acre-foot of generated water during the November 2026 through April 2027 season to fall below that of many alternative water sources, including desalination and taking farmland out of production.
Those projections reflect company expectations, not findings from the published precipitation study.
More Research Needed to Measure Water Reaching the Ground.
The study concludes that drone-based cloud seeding can produce repeated precipitation changes that weather radar can detect and track.
It also identifies important unanswered questions.
Although researchers found strong evidence linking the 71 observed precipitation patterns to cloud seeding, the study did not measure the overall success rate of the company’s operations.
Nor did it establish how much additional water accumulated on the ground.
The researchers called for controlled experiments and measurements closer to the Earth’s surface to better understand how frequently cloud seeding produces precipitation and how much of that precipitation reaches the ground.
Those measurements would help determine how much usable water cloud seeding operations can provide.
Study Citation:
Satrio, Martin, Aimee Matland, Joshua Aikins, Amie Dobracki, Cameron Wessel, Matthew Decker, and Kaitlyn Suski. (2026). “Radar-Observed Cloud Seeding Signatures from UAS-Based Glaciogenic Seeding: The 2025–2026 Rainmaker Season.” Atmosphere, 17(11), Article 1093. Published November 5, 2026.
DOI: 10.3390/atmos17111093
