What is cloud seeding? And how can it help the drying Colorado River?

This story is one part of a broader series about ways to save water from the drying Colorado River. See the full project here.

Water experts across the American West often note that alongside the massive lakes and reservoirs humans have built, the region’s greatest way of storing water is its snowpack.

So why not make it snow when and where we can?

That’s the idea behind the decades-old technology of cloud seeding.

Cloud seeders are already working across the American West and there’s no need for them to stop their work, experts say, but the method isn’t a substantive solution to the water shortage in the Colorado River basin.

“It’s so darned hard to quantify the impact,” Estevan López, the Upper Colorado River Compact Commissioner for New Mexico, said.

In short, when the right type of clouds are near, seeders can agitate the super-chilled water inside them with a chemical compound, usually silver iodide. They spread that compound using planes or even machines strategically placed on the ground. The silver iodide then causes the water to freeze and fall to the ground as snow.

Voila! More snow means more water for the Colorado River Basin, right?

Not necessarily.

Cloud seeding doesn’t create storms out of nowhere, it can only enhance existing storms.

More realistically, the extra snow that might fall as a result of cloud seeding is snow that might have fallen farther downwind of the storm, Jay Famiglietti, director of the Global Institute for Water Security at the University of Saskatchewan, said. So seeding isn’t creating snow so much as changing where and when it falls.

The process can only work with the moisture already in the area, Famiglietti said. And “there’s not enough moisture in the air” to make a big enough difference in the basin’s ongoing drought.

Plus, there’s what’s called the “downwinding effect” to consider, Jennifer Gimbel, senior water policy scholar at Colorado State University’s Water Center, said. If more snow is falling in the West because of cloud seeding, then people further east that might have otherwise received that snow could argue that moisture was effectively taken from them. That perception could create a sort of legal liability, she said.

Source: Read Full Article