Weather and water development officials joked Thursday that they were not responsible for the recent atmospheric change, but that they might not be able to say that for long.

Many states in the West are interested in the weather modification process of cloud seeding, emitting puffs of silver iodide into the clouds above mountain ranges to increase snowfall.

A Thursday meeting at the annual Wyoming Water Association conference in Casper addressed many of the details of cloud seeding and looked at similar programs in Utah and Colorado, as well as Wyoming's plans slated to begin later this year.

"Cloud seeding is not a drought-busting tool," said Barry Lawrence of the Wyoming Water Development Commission. "This is more of a long-term fix."

Lawrence said the nearly $9 million program is expected to run from Nov. 15 through March 30 each year for five years. The eventual goal is to create at 10 percent increase in snowpack by catching some of the moisture as it gathers over mountain ranges before it moves on and evaporates.

Bruce Boe, director of meteorology for Weather Modification Inc., said cloud seeding "helps to improve soil moisture, streamflows, reduce groundwater mining and fill reservoirs."

"Cloud seeding accelerates precipitation," Boe said.

Should the seeding cause precipitation increases that are way above normal levels, Boe said the program will suspend seeding until levels normalize. Suspension will also occur once the target snowpack levels are reached, in advance of large storms, and for avalanche and flood warnings.

Boe said it's unlikely to see any seeding this year due to unanticipated environmental permitting issues, but that the process will begin as soon as possible.

"It's much more important to do it right than to rush into it," Boe said.

Wyoming's cloud-seeding plans include 24 ground-based silver iodide stations and a turbo prop aircraft to speed up ice formation within the clouds. A conservative estimate anticipates the program will cost $8 to $13 per acre foot of precipitation, compared with $2,500 per acre foot to build a new dam and reservoir.

Steve Hunter with the U.S. Bureau of Reclamation said Utah is using liquid propane in addition to silver iodide burners to claim additional moisture. Hunter said he is excited about Wyoming's plans.

"This is an opportunity for Wyoming to lead the way," Hunter said.

News Tracker

* Last we knew: Wyoming officials approved a five-year study to measure the effects of cloud seeding on several mountain ranges.

* The latest: Plans to start seeding by Nov. 15 have been delayed by unforeseen environmental regulations.

* What's next: Officials hope to start seeding Wyoming clouds before the year is over.

Assistant State Editor John Morgan can be reached at (307) 266-0614 or john.morgan@casperstartribune.net.