Cloud seeder believes in program |

Cloud seeder believes in program

SUMMIT COUNTY – Larry Hjermstad believes up to four inches of this weekend’s snowfall can be credited to Denver Water’s cloud-seeding program.

“We seeded the storm,” he said Monday, adding he believes cloud-seeding squeezed an additional 10 to 20 percent of snow out of the system. “It’s the kind of storm that should respond approximately in that range.”

This weekend’s storm left between one and two feet in Summit County, with the highest measurements taken in Breckenridge and Copper Mountain.

Hjermstad operates the program, which began in Summit County this month. A permit granted by state water officials allowed Hjermstad to begin seeding Nov. 1, and the Durango man said the machines began running at 1 that morning.

“The permit was to start the first of November, and that’s when the weather came in,” he said. “It was almost waiting for us.”

The snowfall to date this year is already about 40 percent of last year’s total accumulation. So far for the season, a National Weather Service gauge at Dillon Reservoir has recorded 25 inches, according to dam caretaker Ron McGow. The total snowfall for last season was just 64.5 inches, McGow said.

Denver Water, the Upper Arkansas Water Conservancy District and the Southeastern Colorado Water Conservancy District joined forces this winter to cloud seed in several mountain counties, including Summit. The agencies, all desperate to bolster water supply dramatically reduced by the recent drought, signed a $700,000 contract with Hjermstad, who has cloud-seeded in Eagle County for 27 years.

Denver Water Manager Chips Barry said Monday he was delighted with the snow but hesitated to attribute it to the agency’s new program.

“Judging the amount of snow elsewhere in the state, we would be overly prideful if we claimed all of this – or maybe any of it – was a result of seeding,” he said. “It’s very hard to tell. We hope we added some 10 to 15 percent.

“I’m very encouraged by the early snowfall, but I can’t separate my positive emotional response from anything about seeding. We’ve got a good start to the snowpack, and that’s about all you can say.”

According to the Denver Water contract, plans called for placing 41 generators throughout the mountain region, a dozen to 15 of those in Summit County. The generators release silver iodide into the air when storm clouds pass. If conditions are right, the silver iodide causes ice embryos to grow into snowflakes and fall to earth.

In the county, officials placed generators from Hoosier Pass to Kremmling, about 7 or 8 miles apart, mostly on ranches and campgrounds, Hjermstad said. When he determines storm conditions are right for cloud seeding, Hjermstad places calls to those property owners, asking them to turn the generators on.

Monday morning, Hjermstad said he was still seeding Summit County clouds but planned to order the generators shut down by about noon because he said the forecast called for clearing skies.

Hjermstad said his 28 years of cloud seeding in the Vail area substantiate his faith in cloud seeding.

“We’ve looked at about 16 years of data using two different sets of precipitation (measurement) and found on seeded days we had about 15 percent greater snowfall in the Vail area than what was happening around it, ” he said. “We looked at it in a whole bunch of different ways. We didn’t have to fudge one number – it just jumped right out.”

While he is confident cloud seeding works, Hjermstad also noted that weather patterns during recent weeks have been more normal than during the same period last year.

“We’re looking for a much closer-to-normal winter, and if we can do better than that, that’s fine,” he said.

Jane Reuter can be reached at (970) 668-3998, ext. 229, or by e-mail at

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