Cloud seeding gets off to small start

Star-Tribune correspondent

ENCAMPMENT -- Wyoming's $8.8 million effort to determine whether cloud seeding will provide more water is under way -- sort of.

The first minor airborne seeding of clouds over the Medicine Bow Range took place last week, and additional seeding operations are anticipated during the next month, according to Bruce Boe of Weather Modification Inc. of Fargo, N.D., which is managing the five-year, state-funded pilot project for the Wyoming Water Development Commission.

Last week’s “airborne flare” occurred when a specially equipped aircraft released a small amount of silver iodide into a cloud believed to contain super-cooled liquid water. Only one flare on the aircraft was used during the initial seeding operation; during full activities more than 15 flares on each wing of the airplane will be capable of releasing the silver iodide.

Silver iodide speeds up ice formation within the clouds.

Daily weather monitoring is occurring as part of the project, including the release of balloons from the Saratoga area, Boe said. Additional airplane reconnaissance missions were planned, including one that took place on Wednesday, when Boe outlined the current operations for the Casper Star-Tribune.

This year’s project has been delayed because of the need to have all permits for the airborne seeding in place with the Wyoming state engineer’s office, he said.

Ground-based seeding will not take place until environmental studies are completed on a proposal for 16 stations that would be located in and around the Medicine Bow National Forest. The public comment period on those stations has now closed, and final analysis is under way by the Forest Service, Boe said. He does not expect that to be completed before fall.

Although they had permits in hand for the aerial seeding, Boe said company officials decided to delay any type of seeding operation until after the comment period had concluded with the Forest Service.

Now Weather Modification is prepared to conduct the aerial program, but will only do so for the Snowy Range, particularly in the area of Elk Mountain. No seeding is planned this year on the Sierra Madre Range, Boe said.

Referring to that area, Boe said, “Further south, there is already a lot of snowpack, and there is no need to augment the snowpack.” Further, he said, delaying any seeding operations there “would give the Forest Service an area that has not been affected” by the pilot project.

The two mountain ranges are “pretty similar, and both have a lot of snow,” Boe said.

The Natural Resources Conservation Service on Friday reported snowpack in the Upper North Platte River Basin was 116 percent of average. In the Snowy Range, North French Creek was 129 percent of average, while south Brush Creek was 103 percent of average. In the Sierra Madres, the highest recording was at Old Battle, which has 122 percent of average snowpack, while Webber Springs recorded 109 percent of average.

Boe anticipated a “limited amount of airborne seeding” will still occur this year. And Weather Modification is also continuing to collect data over both mountain ranges, in addition to daily releasing weather balloons from Saratoga to track air currents and other weather factors.

As planned, the project would end every year on March 31, including 2006, he said.

The pilot project also will involve eventual seeding in the Wind River mountains.

The American Meteorological Society estimated earlier that a well-conducted winter cloud seeding program can result in about a 10 percent increase in precipitation.

Wyoming water officials said earlier that a successful program could increase water supply in the state at a cost far less than through dam construction. They estimated cloud seeding could produce water at a cost of about $13 per acre-foot, compared with a cost of about $2,500 per acre foot to build a new dam and reservoir.

An acre foot is the amount of water needed to cover one acre at a depth of a foot.