Can This Army of Drones Solve the West’s Water Crisis?

Cloud seeding isn’t a new technology, but Rainmaker’s innovative approach coupled with the driest stretch parts of the West have seen in some 1,200 years has thrown the practice into renewed prominence—and under renewed scrutiny. It’s notoriously hard to quantify how effective the technique is, and scientists are skeptical of big promises from well-funded enterprises.

Still, as climate change warms the planet, decreasing snowpacks, draining reservoirs, and creating parched landscapes ripe for wildfires, parts of the United States and other countries are desperate for a remedy, pushing companies like Rainmaker to keep innovating.

“We don’t have another solution,” says Katja Friedrich, a professor of atmospheric and oceanic sciences at the University of Colorado Boulder. “What else is solving our water crisis?”

Cloud seeding works by enhancing the natural process that causes precipitation. The clouds we see when we look up at the sky are made of billions of droplets that have formed after evaporating from rivers, lakes, and oceans. As these droplets condense, they become so heavy that they rain or snow down on us. Silver iodide, the most used seeding agent, attracts moisture. As droplets coalesce around one iodide particle, they become so heavy they fall.

This form of weather modification has been practiced since the 1940s, always with the caveat that it is hard to know how much to attribute precipitation to the seeding agents. But around 10 years ago, a team of scientists set out to prove causality. The result was SNOWIE, a 2017 experiment that for the first time confirmed that silver iodide does contribute to snowfall. One 24-minute run of seeding produced over 89 million gallons of water, enough to fill 135 Olympic swimming pools.