Garrett Cammans and his brothers don’t always talk about the toughest times in their work in cloud seeding, like the time one of them got stuck in deep snow on a mountain in the American West and had to walk alone in the dark.
“They work in fairly remote rural areas,” says Cammans. And there were a few close encounters with wild animals that we don’t like to talk about at the family dinner table. »
But snow―as much as possible―is at the heart of the Cammans’ family business, Utah-based North American Weather Consultants, which has cloud seeding contracts throughout the western United States, especially in the Rocky Mountains.
Lately, business has been booming for this company founded over 40 years ago. After two decades of drought, cloud seeding, which involves using aircraft or ground-based equipment to send rain and snow-producing particles into clouds, is booming there.
Colorado has introduced three new programs in the past five years. Wyoming, which began seeding in 2014, added an aerial program in 2018. Utah has steadily increased its fleet of cloud seeding equipment, and the state legislature just approved funding record to continue expanding programs and research.
Much of this growth is due to intense drought pressure on the Colorado River and its tributaries, which provide water to millions of people from Wyoming to Los Angeles.
Not everyone is convinced of the usefulness of cloud seeding. Some experts believe that conserving water is a better, more down-to-earth way to ensure that there will be enough water for everyone. According to them, it is not certain that we manage to produce a little more precipitation thanks to the seeding of clouds.
“It’s always easier to talk about how to get more water than how to use less,” says Kathryn Sorensen of Arizona State University’s Kyl Center for Water Policy. When looking at the problem of over-allocated water from the Colorado River, the numbers are so big that the solution is to use less water, especially in agriculture. From a political point of view, it is very difficult to deal with this situation. »
Membership in the Rockies
But in the Rockies, cloud seeding today enjoys full buy-in from local and national officials eager to find an inexpensive way to increase the amount of water in streams, rivers, and especially in large reservoirs in the Colorado River system, which reached historic lows last year.
Their approach? Send silver iodide into clouds, where moisture binds to particles, forms ice, and falls as snow. This snowpack located in the mountains serves as a cold reserve for the water that is released as it melts.
In Wyoming, aerial cloud seeding aims to increase the snowpack on the western slopes of the Wind River Mountains so that snowmelt flows into the Green River and downstream communities, eventually reach the Colorado River and its reservoirs, including Lake Powell and Lake Mead.
“Cloud seeding is generating water that wouldn’t have been there before,” said Bryan Seppie, chief executive of the Joint Powers Water Board, which provides water to communities in southwest Wyoming. It is simply a benefit for the whole system. »
When the weather is dry and water is scarce in the West, those with long-standing water rights have preference. The distribution of increasingly scarce water has pitted states against each other.
Cloud seeding appears to be a partial solution they can agree on.
Water providers in the lower Colorado River basin contribute about US$1.5 million annually to cloud seeding in the upper basin, where snowmelt feeds the river. Recently, the federal government announced a contribution of US$2.4 million to this effort.
Despite this renewed attention, cloud seeding has been used around the world, and in the Rockies, for more than 50 years.
Additional research
Cloud seeding in the United States has been over-hyped and federal funding dried up in the 1990s and early 2000s, said Frank McDonough, a scientist with the Desert Research Institute in Reno, Nevada.
“Local water officials knew it worked, so they continued to fund it with the states,” McDonnough said. Now, new evidence shows it works. »
A 2017 study of aerial seeding in Idaho found a clear pattern of snowfall on radar that reflected the seeding and offered proof that the method worked.
Utah has calculated how much additional water cloud seeding has created there. It added 186,000 acre-feet of water, an increase of nearly 12%, to the state’s supply in 2018, according to a Division of Water Resources analysis. The agency says the cost was US$2.18 per acre-foot, a fraction of the US$20 California farmers pay for that amount of water.
“The cost per acre-foot was so low that it was a no-brainer,” said Jake Serago, a water resources engineer for the division.
However, Sarah Tessendorf of the National Center for Atmospheric Research stressed that more research is needed to conclusively demonstrate the amount of additional water created by cloud seeding.
“It is very common for people to want to know the additional percentage of precipitation formed,” says M.me Tessendorf, co-author of the Idaho cloud seeding study.
Silver iodide can have a small effect on some clouds and a large effect on others, so it’s the amount created over an entire winter season that matters most, she said. added. “We don’t have an answer on this yet, but we hope to have some in the next few years thanks to the results of our new computer models. »
From one extreme to another
In the foothills north of Boulder, the first cloud seeding project of the Rapidly Growing Frontal Range Urban Corridor of the Rockies north and south of Denver is underway. This winter, two land-based generators pumped silver iodide into the air for the St. Vrain and Left Hand Water Conservancy District.
Each generator is a two-wheeled trailer containing a tank of silver iodide released by a roaring flame fueled by propane and placed atop a metal mast. A communications antenna transmits signals to turn the generator on or off, depending on conditions.
Lately, in the Rockies, the problem is not the lack of snow. Against the backdrop of a wet spring, some cloud seeding generators were shut down over fears that heavy snowfall could cause flooding.
Jonathan Bowler of the Savery-Little Snake River Water Conservancy District, which monitors runoff, says some generators are down in southern Wyoming’s Sierra Madre range, where snow accumulation rivals with the largest thickness ever recorded. “Here, we live and die by humidity,” Bowler said. Too dry is one extreme and too wet is another. But regardless of what the weather will give us, we have to manage. »
For the Wyoming Water Development Commission, which oversees the state’s cloud seeding program, it’s the long-term averages that matter, said Chairman Ron Kailey Jr. “You have to look at the good years, the bad years, and everything in between to determine the success of the program,” Kailey says.