Cloud seeding test coming to and end this year in Winds

Jul 19, 2013 By Bob Moen, Associated Press

Preparations are being made for a final winter of seeding clouds over the Wind River Mountains and other mountain ranges as part of the state's unique research project to determine whether the practice actually works.

"We're just continuing on and methodically continuing down that path to get to the finish line," Barry Lawrence, project manager with the Wyoming Water Development Office, said.

"A lot of good science is going on here, a lot of attention being paid to the project, and we're very pleased with how things have gone so far."

The state has invested about $13 million since 2005 in the project, which seeks to determine whether cloud seeding increases the amount of snowpack in several of the state's mountain ranges. Cloud seeding involves injecting silver iodide into clouds.

Under the right conditions, the chemical can help water droplets grow and fall to the ground.

Facing water shortages and drought conditions, governments around the world and in the United States have undertaken cloud seeding in an attempt to wring more rain and snow from the sky.

Critics say the technique is not proven and could pose a threat to the environment.

Most of Wyoming's water supply comes from winter snowfall in the mountains.

Supporters of the project say increasing the state's winter snowpack would provide more water for communities and irrigation and would be cheaper than building new dams and reservoirs.

The Wyoming project has been hampered by drought conditions that have limited chances for cloud seeding the past two winters.

In order for scientists and researchers to adequately determine whether the cloud seeding has worked, they need a statistically valid set of data, which depends on the number of times cloud seeding is successfully conducted.

Lawrence said researchers succeeded in obtaining 17 cloud seeding cases last winter after getting a low of just 15 the previous winter.

During the first years of the project, when there was no drought, researchers obtained more than 30 cases in some years, he said.

"Going into the fall and into the winter we'll know better how many additional cases we'd like to have," Lawrence said.

"But we're methodically going down that path, and so we're cautiously optimistic, I would guess, that we're going to come up with scientifically credible results."

Scientists will issue a report at the end of 2014 on whether the cloud seeding worked.

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