Denver Water to begin cloud seeding |

Denver Water to begin cloud seeding

What: Public hearing on cloud-seeding program

When: 10 a.m. Sept. 16

Where: Four Points Sheraton, Silverthorne

How it works:

Generators introduce an ice-forming nucleating agent, e.g., silver iodide, into the appropriate cloud regions, causing supercooled liquid water droplets to freeze. Once these droplets freeze, the initial ice embryos grow at the expense of the water droplets around them and through contact with these neighboring water droplets. These embryos, if they remain in favorable cloud conditions, will grow into snowflakes, falling to the surface as snow if surface temperatures are below or near freezing.

SUMMIT COUNTY – Larry Hjermstad believes Summit County’s skiers will enjoy a better snow season this year than last. He stakes his livelihood on it.

“No matter what kind of winter you would have had, it will be a better winter because of cloud seeding,” said Hjermstad, founder of Western Weather Consultants. “We’ve seen it consistently in Vail.

“If you’re going to have a 70 percent of normal (snowfall) winter, you’ll end up with a 90 percent of normal winter,” he said. “That’s the kind of increases we’ve tended to see with these weather patterns.”

Hjermstad has been cloud seeding in Vail for 27 years, where he claims increases in snowfall ranging from 16 to 30 percent. This winter, Hjermstad is working with Denver Water to cloud seed in several other mountain counties, including Summit. A total of 41 generators are planned in the mountain region. A dozen to 15 of them will be placed in Summit County, Hjermstad said.

Denver Water’s primary goal isn’t to make the ski areas happy. It’s to bolster snowpack that will melt into drainages leading to the agency’s now-drought-starved reservoirs, among them Dillon Reservoir.

But ski areas are expected to benefit from the program, too, and Denver Water is hoping they’ll pay for that enhancement. While Denver Water will pay up to 58 percent of this winter’s program – about $400,000 – officials there are asking ski areas in the path of the cloud-seeding generators to chip in the remaining $300,000. Total cost of the program is $700,000. Seeding is set to begin this fall and continue through the winter, and Denver Water Manager Chips Barry said it’s “likely to be a multi-year program.”

Local ski areas haven’t yet made financial commitments to Denver Water’s winter cloud-seeding program, but officials at Summit County’s resorts all say they’re considering it.

Success stories

In Eagle County, Vail Mountain Chief Operation Officer Bill Jensen said Denver Water officials have asked to use Vail’s cloud-seeding generators beyond the months Vail normally uses them. Since that might bring Vail extra snow, Jensen said that’s not a tough decision to make.

Jensen believes firmly in the benefits of cloud seeding. On average, he believes it ups snowfall by 15 percent. He also can point to particular storms during which he believes cloud seeding was key.

“Two years ago, Vail had two 30-inch powder days in the back bowls,” he said. “On those same days, at other ski resorts (including Summit ski areas), the most snow received was 7 inches.

“I am very confident in it for the nominal amount of money we spend, in our case $60,000 to $80,000 a year. For the equivalent of one night’s snowmaking, I get snow on 5,300 acres instead of six from snowmaking.”

Barry said the benefits of cloud seeding are “hard to prove,” but it’s intriguing enough to give it a try, particularly when some reservoirs within Denver Water’s system are sitting at 60 percent of capacity.

“I think in these kinds of circumstances, it’s important to do everything you can do,” he said. It’s also fairly low cost.”

The skeptics

But not everyone believes cloud seeding works. During a recent meeting of the Summit Leadership Forum, County Commissioner Tom Long said Denver Water’s program “is a good PR move.”

Jim Spenst, Copper Mountain’s director of operations, said he’s spent 20 years studying the idea, and he still can’t say whether or not it works. Copper Mountain seeded clouds from the late ’70s to the mid-’80s,

“Vail claims a 15 percent increase, but it’s all circumstantial evidence,” he said. “There’s too much voodoo to it.”

But assistant state climatologist Nolan Doesken isn’t so sure. Doesken, who works at the Fort Collins-based Colorado Climate Center, said he leans “to the yes side” of the never-ending debate about cloud seeding’s effectiveness.

“In the laboratory, it works,” he said. “It harvests liquid water that’s in the clouds and converts it into snowflakes that bring moisture to the ground. In nature, it’s hard to know what’s going on, but it works well enough in the laboratory that you’ve got to think it’s working in nature.”

Hjermstad claims there’s no truth to the contention that cloud seeding steals snow from downwind areas; for instance, that Vail’s program denies Copper its normal amount of snowfall, or that eastern Colorado ranchers will suffer from Denver Water’s mountain program.

“That’s totally not true. It just isn’t that way,” Hjermstad said. “Research was done specifically downwind just to see what was happening showed – if anything – there was about a 2 to 3 percent increase. Because more precipitation is falling out of these cloud systems, that is releasing extra energy into the weather system itself which increases the circulation. The atmosphere is not a fixed box. It’s a very elastic medium”

Promising as it sounds, however, climatologist Doesken pointed out that cloud seeding doesn’t work without clouds.

“You can’t make it out of nothing,” he said. “You basically have to have a fairly large number of storm systems to have this do you any good whatsoever. This is not something you do to rescue yourself out of drought. This is something you do as a long-term water resources management strategy.”

And at this date, Doesken said it’s too soon to predict what this winter will bring.

Jane Reuter can be reached at 668-3998, ext. 229, or by e-mail at

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