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Idaho Power seeks second plane to cloud seed in Upper Snake

December 28, 2018 GMT

Idaho Power Co. officials hope to fund a second aircraft for cloud seeding in the Upper Snake Basin as they expand a collaborative program that has significantly bolstered snowpacks in a few targeted watersheds.

Company officials say they’ve asked partners in the weather modification program -- the Idaho Department of Water Resources and state water users -- to increase contributions to help them continue with the build-out.

The program uses a network of three aircraft and 57 ground-based generators that emit silver iodide into storm clouds, increasing snowfall from storms in key areas to help the company produce more hydro-power for customers. Water vapor condenses on the silver iodide particles, which then fall as additional droplets.

Idaho Power officials hope to have a fourth aircraft for the program by next winter.

“That would be a substantial increase in our seeding ability in the Upper Snake,” said Shaun Parkinson, Idaho Power’s water resources leader. “We do need to work with water users to share some of the expense.”

Idaho Power’s current Upper Snake aircraft is supplemented by 25 remotely operated generators, which burn a solution containing silver iodide, so the vapor can rise into the clouds. High Country Resource, Conservation and Development operates another 25 generations in the Upper Snake through a separate program.

Last winter, Idaho Power officials estimate their efforts contributed an extra million acre-feet of water to Idaho’s mountain snowpack. Parkinson said it was an average winter, and the cost of the extra water came to about $3.30 per acre foot. Parkinson said the going rate for leasing an acre-foot of water is about $20.

He estimated the additional water supply achieved through cloud seeding last winter would have produced sufficient hydro-power to accommodate 65,000 homes for a year.

“We’ve looked at a lot of different runoff scenarios, and the benefit to cost for customers ranges from a really pessimistic dry year of two to one to four or five to one, depending on water conditions,” Parkinson said. “It’s very cost effective.”

The program started in 2003, and seeding takes place annually when storms pass through between Nov. 1 and April 30. Program officials measure success by comparing snowfall from target areas with areas that have historically received similar amounts of precipitation from common storms but are outside of the area of impact for seeding.

Last winter, officials estimate they boosted water from snowpack by 8.9 percent in the Henry’s Fork drainage, 6.1 percent from the Snake River headwaters through Palisades Reservoir, 8.7 percent in the Wood River Basin, 11.5 percent in the Boise Basin and 12 percent in the Payette Basin.

The IDWR contributed $780,000 toward the $3.3 million program in funding year 2018, and Parkinson said the department has discussed the possibility of increasing its contribution going forward. The Big Wood, Little Wood and Fish Creek canal companies collectively contribute $125,000 and area also mulling the possibility of increasing their contribution, but making it through their Water District 37.

David Stephenson, general manager of Big Wood Canal Co., said the water district will discuss increased funding for cloud seeding during its annual meeting in January.

“It’s been a good program, and it’s a pretty cheap acre-foot of water when you put a pencil to it,” Stephenson said.

Water District 1, based in Idaho Falls, contributed $200,000. Water District 63, which covers the Boise Basin, pitched in $125,000. Idaho Ground Water Appropriators, Inc., gave $25,000.

Idaho Power started using the current aircraft serving the Upper Snake in 2015.

Derek Blestrud, a senior atmospheric scientist with Idaho Power, said the program obtained a better understanding of cloud seeding science and received data to hone its models through a research project last winter funded by the National Science Foundation.

The project, called Seeded and Natural Ornagraphic Wintertime Clouds -- the Idaho Experiment -- involved scientists from University of Illinois, University of Wyoming and University of Colorado. The researchers set up trailers with Doppler radar weather stations on mountain tops in the Payette Basin. They also used their aircraft to observe the changes taking place within storm clouds during cloud seeding.

“SNOWIE is the most comprehensive study to date on cloud seeding in winter,” Nick Anderson, program director with NSF’s Division of Atmospheric and Geospace Sciences, said in a press release.

Blestrud said findings of the study have been published in two high-level scientific journals, and another paper is due for publication in January’s edition of “Bulletin of the American Meteorological Society.” Blestrud said several more papers are in development from the project.

“From this whole project, we were able to see some phenomenal data. We could see the change in microphysics of the storm as seeding occurred,” Blestrud said. “It really helped us identify what parts of the storm are seedable.”