State to review cloud-seeding efforts |

State to review cloud-seeding efforts

Bob Berwyn
Summit County correspondent
Aspen, CO Colorado

SUMMIT COUNTY – A widespread cloud-seeding operation that includes parts of Summit County is up for re-authorization by the Colorado Water Conservation Board.

Durango-based Western Weather Consultants wants to continue its cloud-seeding operations on behalf of water providers like Denver Water, Colorado Springs Utilities and the Upper Arkansas Water Conservancy District.

By using ground-based generators to introduce tiny silver iodide particles into approaching storms, Western Weather claims it can boost precipitation by up to 15 percent under ideal conditions.

First used in the 1960s, cloud-seeding has become routine in parts of Colorado. While scientific studies on the process are not conclusive, there is some evidence that it can boost snowfall, although the Aspen Skiing Co. has traditionally avoided the practice.

Vail Resorts has been seeding clouds upwind of its Eagle County resorts for about 30 years. Hjermstad said the same silver iodide generators used to boost snowfall at Vail and Beaver Creek during a southwest flow also enhance precipitation for the Homestake collection system and Ruedi Reservoir during a northwest flow.

But Summit County resort executives have been a little more skeptical of the process. Hjermstad said he may approach local government officials and resort executives to discuss the potential for stepping up cloud-seeding efforts in the Summit County area.

Denver Water spent about $1.1 million in 2002-2003 on cloud-seeding in the Upper Blue Basin, estimating a gain of about 35,000 to 50,000 acre-feet of water, at a cost of $12-$23 per acre-foot.

During that time, Denver Water did a pair of studies to evaluate the program, with conflicting results. A statistical analysis of snowfall data indicated the seeding was effective, boosting accumulations by about 14 percent.

But a second study did not find significant traces of silver iodide in the intended target areas, indicating “a failure to routinely seed the intended cloud regions.”

One recent report from the Bureau of Reclamation concludes that widespread cloud-seeding in the Colorado River Basin could generate up to 1 million acre-feet of additional water in an average year, with half that amount in a dry year. That report is online at:


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