Rainmaker’s drone cloud-seeding test raises questions about impact and limits

The Alaska test could make cloud seeding more visible, while also sharpening scrutiny of what it adds and how its effects are tracked.

Rainmaker, a San Francisco start-up, has drawn attention after using drones for cloud seeding near Homer, Alaska, where it says it created the equivalent of 19 million US gallons of water in three hours. The test matters because cloud seeding is an old but still limited weather-modification technique, and the company is now facing questions about both environmental monitoring and how much rain such efforts can realistically add. Rainmaker’s CEO, Augustus Doricko, says the company releases silver iodide at 20 grams per flight and that the resulting ground-level concentration is far below FDA limits. The wider field is also shifting: specialists say well-targeted seeding can add roughly 5% to 10% more precipitation under the right conditions, while Recast Systems is testing a protein-based alternative that it says is biodegradable and more efficient than silver iodide.