Brief by Allen Best
Snow – November 2002 – Colorado Central Magazine
With streams running at their lowest in 150 years, ski areas and cities in Colorado have been looking at once discarded ideas, including cloud-seeding. Deployed extensively after the last benchmark drought winter, 1976-77, the cloud-seeding generators have since been largely abandoned. The only consistent holdouts were Vail and Beaver Creek.
But now, Denver plans to spend $700,000 on cloud-seeding, and some ski areas are also looking into it, among them Crested Butte.
How good are the claims? Scientists from Colorado State University involved with cloud-seeding programs in the 1970s insist that the process augments precipitation by about 15 percent. At Vail, ski area officials have reviewed records for the last 16 years and concluded that 8% to 22% more snow fell at Vail and Beaver Creek as compared with other resorts, and they say geography alone cannot explain the difference.
Larry Hjermstand, the Durango-based businessman who has done most of the cloud-seeding for the last 25 years, estimates snowpacks can be augmented by up to 30%.
Bill Jensen, Vail Mountain’s chief operating officer, who is relatively new to the resort, says he’s sold on the idea. He told the Crested Butte News that he believes cloud-seeding would coax two or three more inches of snow from a passing storm.
Clouds must be present for seeding. When those clouds arrive, generators spew silver iodide into the sky. The silver iodide is supposed to be like the dust particles around which snow flakes are formed. One company, North American Weather Consultants, of Sandy, Utah, maintains that the silver iodide has “no significant impact on the environment,” resulting in a concentration of only 0.1 microgram of silver, well below the threshold of 50 micrograms per liter recommended by the U.S. Public Health Service.
Others are skeptical of claims made on behalf of cloud-seeding, and that would probably include Colorado state government, which grants permits for cloud-seeding. Twice it has rejected claims from residents who claimed adversities caused by cloud-seeding.
In the late 1970s, ranchers near Steamboat Springs concluded that one of the greatest snowpacks on record was caused by snowmaking, and demanded reimbursement for their extra costs in feeding cattle. They didn’t get it. Leadville residents in the mid-1980s had much the same argument, claiming Vail’s cloud-seeding caused them extra snow-removal costs and, in general, more miserable winters. The cloud-seeding didn’t stop, though, nor did they get checks in the mail.