From KJCT.com (Dann Cianca):
George Stowell lives in Gunnison and is the operator of one of the many cloud seeding generators in the county. The generator is actually located in his back yard and works by injecting the cloud seeding solution into a propane burner. The heat carries the particulate that results into the upper levels of the atmosphere where the particles act, in simple terms, as an attractive place for tiny water vapor droplets to gather. Could seeding works by increasing the efficiency by which rain drops or ice crystals form within the cloud. Atmospheric conditions have to be just right for this to work, however, so the generator is typically only turned on a few times per season. The state issues permits through the Colorado Water Conservation Board and these permits only allow the operators to seed at when the permit area will be affected. This basically happens when the wind is blowing a certain way.
The Gunnison County program has been ongoing for about ten years and is partially sponsored by the county itself. The county isn’t actually the largest source of funding for the program however as many other interests which include agriculture groups, municipal water districts and even ski resorts contribute…
Operators of these programs say that the science is sound and that it provides good results. With Colorado’s dependency on water, they say that having extra snow-pack can make a huge difference on the economy of the state. That is why these programs have expanded over the years to include many areas of Western Colorado. Generators exist in the San Juans, the Upper Gunnison River Basin, the Grand Mesa area and even near Vail to name a few.