Seven seeding days. A national government watching every reading. And a rainfall swing that ran as high as 500% above baseline, confirmed independently rather than reported by the company that built the equipment.
Rainfall Increase
300–500%
Above what the same storm systems would have produced untreated.
Operational Success
90%+
Across a range of atmospheric conditions over seven seeding days.
Effect Onset
<10 min
From launch to confirmed rainfall boost reaching the ground.
Coverage per Launcher
80,000 ha
Rated coverage for each SOBLI ground station in the deployment.
Key Takeaways
- Rainfall increased 300–500% above baseline across seven seeding days, independently validated rather than self-reported by Selerys.
- Romania’s AASNACP, under the Ministry of Agriculture, ran the radar monitoring and statistical analysis itself.
- Seeding effects appeared within 10 minutes of launch and held for 30 to 60 minutes, confirmed by radar and soil-moisture readings.
- Each SOBLI launch station covers up to 80,000 hectares, scaling well past what aircraft or ground-based generators can reach in the same window.
- The same LAICO balloon platform can be redirected to hail mitigation, snow enhancement, or fog dispersal without new hardware.
A National-Scale Trial, Not a Pilot
In November and December 2022, Romania ran a nationwide test of automated balloon seeding, supported by the Romanian National Agency for Hail Suppression and Precipitation Enhancement (AASNACP), under the Ministry of Agriculture. The agency didn’t just sign off on the trial. It ran the radar monitoring and the statistical analysis itself, which is what makes the result worth taking seriously: the data wasn’t self-reported by Selerys.
The technology behind it was Selerys’s LAICO balloon system, launched from SOBLI (Self-Operating Balloon Launcher Instrument) ground stations. Each station is solar-powered, remotely commanded, and can move from a launch decision to seeding in under five minutes.
The Numbers
Across seven active seeding days, rainfall consistently landed well above what the same storm systems would have produced untreated:
| Seeding night | Untreated (l/m²) | Treated (l/m²) |
|---|---|---|
| Nov 16–17 | 0.5 | 5 |
| Nov 17–18 | 9 | 21 |
| Nov 18–19 | 1 | 5.5 |
| Nov 19–20 | 3 | 8 |
| Nov 23–24 | 4 | 12 |
| Dec 6–7 | 0.5 | 3 |
| Dec 11 | 0.5 | 4 |
That works out to a 300–500% increase in rainfall compared to baseline, with more than 90% operational success across a range of atmospheric conditions. Seeding effects showed up within 10 minutes of a launch and held for 30 to 60 minutes afterward, long enough for radar and soil-moisture readings to confirm the boost reached the ground rather than evaporating on the way down.
Why the Balloon Made the Difference
A storm cell is short-lived. A single cell runs through its life cycle in about 20 minutes, and the real window to treat it, the point where seeding actually changes the outcome, is closer to 10. An aircraft has to be airborne and on target before that window closes, and aviation rules only allow one manned aircraft per storm cell at a time. If a storm throws up three cells at once, a plane treats them one after another, if it can reach them at all in time.
A LAICO network doesn’t run into that limit. Several SOBLI stations can launch balloons at multiple storm cells in the same window, and because each balloon streams its GPS position and radiosounding readings back to Selerys’s CIRRUS software in real time, the system builds a full vertical profile of the cloud from a single ascent, instead of the several passes an aircraft needs to piece together the same picture.
Each launcher in the Romania deployment was rated to cover up to 80,000 hectares, scaling the trial well past what a single aircraft or a network of ground-based generators could realistically reach in the same window.
What It Means for Water-Stressed Regions
Romania ran this trial because rainfall variability was already putting pressure on its agricultural regions, and that pressure isn’t going away on its own. Farmers and local officials involved in the trial described a practical difference: better water availability through dry stretches, and more confidence in a technology they watched work in real time instead of reading about months later in a report.
An independent, government-run validation at this scale is rare in weather modification. Most operators publish their own numbers and ask you to trust them. Romania’s Ministry of Agriculture published these.
Where This Fits Into Selerys’s Broader Results
Rain enhancement is one of four use cases Selerys runs on the same LAICO balloon platform, alongside hail mitigation, snow enhancement, and fog dispersal. The underlying hardware doesn’t change between them. What changes is the seeding agent and the altitude it’s released at: hygroscopic salt for rain and snow enhancement, silver iodide or hygroscopic salt for hail mitigation, released either inside the cloud or, for fog, at ground level where the fog itself sits.
That consistency matters for a region deciding whether to adopt the technology. A network built for rain enhancement in a dry season can be redirected toward hail mitigation the following spring, without new hardware and without retraining an operations team on a different system.
Frequently Asked Questions
How much did rainfall increase during Romania’s national balloon-seeding trial?
Rainfall increased 300–500% above what the same storm systems would have produced untreated, measured across seven active seeding days between November and December 2022.
Who validated the results of Romania’s cloud seeding trial?
The Romanian National Agency for Hail Suppression and Precipitation Enhancement (AASNACP), under the Ministry of Agriculture, ran the radar monitoring and statistical analysis itself rather than relying on Selerys’s own reporting.
How quickly does balloon seeding affect rainfall?
Seeding effects appeared within 10 minutes of a balloon launch and held for 30 to 60 minutes afterward, confirmed by radar and soil-moisture readings showing the boost reached the ground.
How much area can one balloon launch station cover?
Each SOBLI launch station in the Romania deployment was rated to cover up to 80,000 hectares, scaling well past what a single aircraft or a network of ground-based generators could realistically reach in the same window.
Can the same balloon system be used for hail mitigation instead of rain enhancement?
Yes. Rain enhancement, hail mitigation, snow enhancement, and fog dispersal all run on the same LAICO balloon platform — only the seeding agent and release altitude change, so a network can be redirected between use cases without new hardware or retraining.
