No one can control the weather, but scientists have done what they can to encourage snowfall in Colorado by cloud seeding for decades, and now they are working to improve it locally.

On Monday meteorologist, Marta Nelson, installed a temporary radiometer at Jackson Lake near the Mancos Water Conservancy District.

The instrument is able to determine the best combination of water content in clouds and temperature to use a cloud-seeding generator.

Cloud-seeding generators throw up silver iodide into the atmosphere to harvest the extra water because snow will form around it.

"We can see relative humidity and vapor and the potential for a cloud to form. We can also see inside a cloud that's already formed, so if we're looking for liquid water versus ice that is frozen in the cloud the radiometer can tell the difference and help tell the cloud seeding people know when to run the generators or when it's not going to do any good," she said. Nelson works for Radiometrics, Corp., based in Boulder, which installs similar machines all over the world.

The new data will also help scientists decide if the local cloud seeding generator at Spring Creek should be run later into the winter season, said Jeff Tilley, director of weather modification at the Desert Research Institute, in Reno. The Institute operates the local cloud-seeding generator remotely. The data that is collected over the next month will be applied to operations next winter because the Spring Creek generator is almost out of cloud-seeding solution, he said.

The Institute is collaborating with the Colorado Water Conservation Board on the project, and the board is paying the $8,500 to lease the radiometer for a month.

Across the state, about $1 million is spent on cloud seeding, and about 65 percent of the funds are provided by local entities such as ski areas, water districts, and towns. The other 35 percent of the funds are provided by state and other funding.

The generator near Mancos has been in place for about five years, and in that time there has been some benefit in the area, Tilley said.

"The impression we have is that we have seen some difference," he said.

Cloud seeding is safe because silver iodide won't break down in any way that's harmful, Nelson said.

There are about 32 cloud-seeding machines in this region. However, the solution for the machines is very expensive. For example, enough solution to run a generator for a season will run about $10,000.

Researchers hope the temporary radiometer will help them use the generator more efficiently.

The Desert Research Institute is interested this area, in part, because the water feeds the Colorado River and supplies water to Nevada and California. The Institute works to improve water supplies across the basins that supply the Colorado River, Tilley said.

The snowpack that supplies the Colorado River is above average this year, but it would take five years of strong snowfall to offset the drought, Tilley said.

Nelson has heard concerns about moisture not reaching the eastern plains because of cloud seeding. But the water for areas West of the Rocky Mountains comes mainly from the Pacific and Water to the east of the mountains comes from the Gulf of Mexico.

"Because the moisture comes from two different areas, we're just making sure that all of it that can fall does, because a lot of these counties face severe droughts in the summertime," she said.

mshinn@cortezjournal.com