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As the Southwest dries out, water managers increasingly look to cloud seeding

Officials look for spot in San Juan Mountains for new generator
Eric Hjermstad, co-owner of Western Weather Consultants, adjusts the amount of silver iodide released as he demonstrates a cloud-seeding device south of La Plata Canyon. Water managers announced recently they will invest in another remote cloud-seeding generator in Southwest Colorado.

Southwest Colorado has long been considered part of the arid West. But as a decades-long drought grips the region, and the population only increases, adequate water supply has become a greater concern to farmers, urban planners and ski resorts.

That is why water managers in Southwest Colorado plan to increase investments in cloud-seeding infrastructure beginning this year.

For decades, Western states have tried to offset long-term drying trends and dwindling water supplies of the region by sending up a specialized concoction into the atmosphere as winter storms approach, which proponents say boosts snowfall.

Across a sliver of Colorado from Telluride to Pagosa Springs, a total of 36 cloud-seeding generators are strategically placed, typically 5 miles apart, to cover a wide range of the high country of the San Juan Mountains for this purpose.

Cloud seeding is a relatively simple process where a propane-fired generator sends silver iodide into the atmosphere before and during winter storms. Eric Hjermstad, co-owner of Western Weather Consultants, said there are nearly 40 generators scattered throughout Southwest Colorado.

In 2020, the Southwestern Water Conservation District has set aside $27,000 for a new remote generator. While the station’s location is being decided, the aim is to place it at a higher elevation site where there is a gap in the network of generators.

“The majority of our water supply comes from snowpack, so if we can provide any additional amount, it has a huge benefit to our basin,” said Frank Kugel, executive director of SWCD, which represents nine counties in Southwest Colorado.

Waters managers who rely on the Colorado River are dealing with an array of issues as more people move into the region and demands increase on a waterway that is seeing less water every year because of issues directly related to climate change.

In adapting to this new reality, cloud seeding, they say, is just one part of the attempted solution.

How it works

People have been tinkering with the idea of shooting a solution into the air to squeeze out more moisture from clouds and storms since the late 1800s, but the practice didn’t take hold until the latter part of the 20th century.

Cloud seeding sends silver iodide into the atmosphere to boost the amount of snowfall in a storm. Supporters say studies have shown the substance has no adverse environmental impact.

In essence, the process is relatively simple.

A propane-fired generator sends silver iodide (a dust particle that helps form ice crystals) into the atmosphere hours before and during winter storms. Shifting winds take and disperse the silver iodide into the clouds, where it grows into a snowflake after encountering moisture.

Eric Hjermstad, co-owner of Western Weather Consultants, which operates the generators in Southwest Colorado, said a single station’s range can reach 8 to 15 miles downwind, with a width of about 3 miles.

On Thursday night, for instance, Hjermstad fired up the generators as a storm entered the region.

“We’ll keep it running until about 3 p.m. (Friday) when the storm moves out,” he said.

Does it work?

How much additional snow falls as a result of cloud seeding has been a hot topic among water managers for years, and most agree, more detailed research needs to happen to pin down just how much additional snow is extracted from the practice.

The exact impacts of cloud seeding needs more study, water managers say. But most agree the practice boosts snowfall from a storm by 2% to 15%.

Yet, most accept an estimated range between 2% to 15% more snow per storm.

Statewide, about $1.2 million is spent annually toward cloud seeding, with money coming from local and state water districts, as well as lower basin states that rely on the Colorado River, said Andrew Rickert, program manager for the Colorado Water Conservation Board.

Supporters of the project have said that for every $1 in cost, about $3 worth of water is produced.

“From all the reports I get, the money we’re spending is nowhere near the benefits we’re getting in water supply,” Rickert said. “And with people’s increased interest in water management and drought, cloud seeding is getting more attention than ever.”

The downsides?

Over the years, there’s been critiques that cloud seeding extracts moisture out of storms before Mother Nature intended, which could be considered stealing from other states. And, questions are consistently raised about dumping silver iodide into the atmosphere.

But research and studies have dispelled such concerns. Silver iodide, for example, has not been proven to be harmful to the environment, even after five decades of use in the United States, water managers with CWCB have previously said.

As more people move into the arid West, demands on water continue to increase. As a result, water managers are looking for all kinds of ways to conserve and add more water into supplies.

Cloud seeding is seen among water managers as just one part of addressing water shortages, along with better conservation practices and removing invasive vegetation that sucks up water. Yet, the practice is unique in that it is the only identifiable way to augment supplies.

“That’s why we’re so invested on a state level,” Rickert said.

The future

Better technology, more generators in high-elevation spots and more stations in general are the top priority with cloud seeding going further.

Experiments have been conducted in recent years that show releasing silver iodide by plane gets more out of storms, but the practice is expensive, and cost-prohibitive, Kugel said.

Southwestern Water Conservation District, along with its partners, will take the coming weeks to find the best spot for the new remote generator in the region. The district spends about $117,000 on the entire cloud-seeding effort in the region.

“We do represent a broad constituency across nine counties, so we want to make sure everyone receives benefits,” he said. “With climate change and our reduction in supplies, I think we’re eager to continue to expand and improve the weather-modification efforts in our basin.”

jromeo@durangoherald.com



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