Old tech, new urgency: The precipitation-catalyzing properties of silver iodide were first explored in the 1940s by American chemists and engineers, but the field remained a small niche. Now, with 40% of people worldwide affected by water scarcity and a growing number of reservoirs facing climate stress, cloud seeding is receiving global interest. “It’s becoming almost like, hey, we have to do this, because there’s just too many people and too many demands on these water resources,” says McDonough. A growing number of government-run cloud-seeding programs around the world are now working to increase rainfall and snowpack, and even manipulating the timing of precipitation to prevent large hailstorms, reduce air pollution, and minimize flood risk. The private sector is also taking note: One cloud-seeding startup, Rainmaker, recently raised millions.
Generating results: At the end of each winter, the snowmakers dig into the data to see what impact they’ve had. In the past, McDonough says, his seeding has increased snowpack by 5% to 10%. That’s not enough to end a drought, but the DRI estimates that the cloud seeding around Reno, Nevada, alone adds enough precipitation to keep about 40,000 households supplied. And for some hydroelectric projects, “a 1% increase is worth millions of dollars,” McDonough says. “Water is really valuable out here in the West.”