Cloud seeding to continue in Rockies |

Cloud seeding to continue in Rockies

Jane Stebbins

SUMMIT COUNTY – Summit County can expect 12 to 14 percent more snow than usual this season if cloud-seeding efforts pan out as resort and Denver Water officials hope.

Western Weather Consultants of Durango has been working with Vail Resorts for 28 years and will enter its second winter of seeding clouds in Summit County.

Denver Water, which owns Dillon Reservoir and significant water rights in Summit County, commissioned the program in Summit County. Western Weather has five seeding generators along the eastern part of the Gore Range and an additional 28 along the Blue River from Green Mountain Reservoir to Hoosier Pass.

Cloud seeding involves using the generators to burn and vaporize small amounts of silver iodide into the atmosphere. Water clings to the chemical, making it heavy enough to fall from the cloud.

Although many studies debunk cloud seeding, local ski areas and Denver water officials are sold on the procedure. They say that most of the studies conducted on cloud seeding have focused on programs on the West Coast, where storms are generally wetter and heavier. That data, they say, can’t be extrapolated to Colorado.

“It’s been very effective,” said Larry Hjermstad, manager of Western Weather Consultants, who is contracted to Vail Resorts, Denver Water and an array of other entities throughout Colorado. “When we compare what happens outside the Vail area, we’re seeing increases in the range of 15 to 24 percent.”

Ski resorts say the operations are cost effective, too. According to Vail Resorts Chief Operations Officer Bill Jensen, it costs $58,000 a month to seed a wide area. That compares with $50,000 a night to blow snow on eight acres.

“The success is really tough to measure,” admitted Christina Schleicher, Vail Resort’s corporate communications manager. “But it’s something we believe in. Some (studies) say it increases snowfall by 15 percent, and we have had

Numbers aren’t yet available for Summit County, where cloud seeding has only been done for one winter. But Hjermstad believes last year’s efforts yielded similar results as those in the Eagle Valley.

“We had good fortune from many standpoints,” he said of last year’s precipitation. “We had that good snowfall in March, and I think with the seeding and that one storm system, we filled the reservoir.”

Denver Water officials worried the reservoir wouldn’t fill without a good snow year. Dillon Reservoir was a little over half full – more full than any other Denver Water reservoir – before the March storm hit, dumping anywhere from 2 to 5 feet of snow on Summit County.

Hjermstad believes seeding contributed about 10 to 12 percent of that snowfall, even though he was only able to seed clouds during a third of the storm because of avalanche danger.

“That just shows the limitations of what man can do with weather,” he said. “Someone up there is doing it much more efficiently, and we can’t match him.”

How much water can be eked out of a cloud depends on air temperature, the amount of moisture in the cloud, wind direction and an array of other factors. As a storm moves through the area, seeding efforts ramp up; as the storm fades, generators are shut down and data is collected.

Climatologist Klaus Wolter of the National Oceanic and Atmospheric Center in Boulder is predicting below normal precipitation through December throughout the state, but normal precipitation in central Colorado. In mid-November, he will update his forecast for the rest of the winter.

Hjermstad’s not sure how this year’s seeding will go.

“It’s hard to argue with success,” Wolter said. “The fact the mountains did so much better, the highest precipitations are right over (Summit County). This winter, it seems to have worked.”

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