FEBRUARY 26, 2025
Photo – Aircraft loaded with silver iodide – Bigfoot99 file photo
The Wyoming House of Representatives voted to defund the state’s cloud seeding programs.
Last November, the Wyoming Water Development Commission and Select Water Committee approved a nearly $1.2 million request from Barry Lawrance, Deputy Director of Planning at the Wyoming Water Development Office. Lawrance asked for $875,000 to pay for aerial cloud seeding in the Sierra Madres and Snowy Range Mountains.
Lawrence also asked for $322,143 to fund ground-based cloud seeding in the Wind River and Sierra Madre Mountains.
Cloud seeding involves dispersing silver iodide into clouds, either from airplanes or ground-based platforms, to encourage the formation of ice crystals, which may enhance precipitation. In Wyoming, cloud seeding is used to increase snowpack in the Sierra Madre, Snowy Range, and Wind River Mountains.
Both funding requests were approved by the Wyoming Water Development Commission and Select Water Committee. However, state legislatures had a different plan.
Speaking at the February 10th House of Representatives meeting, Lincoln and Sublette County Republican Mike Schmid introduced an amendment to the $114 million Omnibus Water Bill, or House Bill 117, to remove the $1.2 million allocated to fund cloud seeding projects. Representative Schmid questioned the effectiveness of the program and blamed the chemical used in cloud seeding operations on the declining big horn sheep population in the Wind River Mountains.
Representative Schmid said cloud seeding programs may also have a negative effect on the state’s glaciers. By artificially causing snowfall in other locations, cloud seeding takes needed precipitation away from the glaciers. Additionally, Representative Schmid said silver iodide can coat the glaciers, increasing the rate at which they melt.
Representative Schmid asked to end funding for cloud seeding until more research can be done on the negative impacts of the program.
Laramie County Republican Bob Nicholas refuted the claim that silver iodide has caused or contributed to the decline in big horn sheep populations. Representative Nicholas stated that the Wyoming Game and Fish Department has conducted numerous studies on bighorn sheep and found no connection between their declining numbers and cloud seeding.
Representative Nicholas also refuted claims that cloud seeding is causing glaciers to melt, saying that the increased snowfall is actually benefiting the glaciers and downstream irrigators.
Sheridan County Republican Laurie Bratten spoke out in support of the amendment to end cloud seeding funding. Representative Bratten said she received an email, presumably from the Wyoming Water Development Office, mentioning how effective the program has been over the last two decades. However, links contained in the email did not lead the legislator to studies supporting the claims.
After conducting her own research, Representative Bratten said she found the study, the Wyoming Water Development Office used to demonstrate the effectiveness of the cloud seeding program, and noted that it relied solely on digital simulations.
Sweetwater County Republican J.T. Larson said from 2005 through 2014, the National Center for Atmospheric Research, also known as NCAR, conducted a study on the effectiveness of cloud seeding within the Medicine Bow and Sierra Madre Mountain ranges. Representative Larson said the study, which used both computer modeling and physical measurements, showed an average increase of 9,500-acre feet of water in the North Platte and Little Snake River basins.
Representative Larson said the NCAR study showed that the average cost of aerial cloud seeding was $81.87 per acre foot.
Albany County Democrat Karlee Provenza said she supported the amendment but clarified that scientists have determined that the silver iodide used in cloud seeding is not contributing to the decreased big horn sheep population.
The House Committee of the Whole passed Representative Schmid’s amendment to cut the $1.2 million for cloud seeding programs out of the $114 million Omnibus Water Bill.
The bill also allocated $2.8 million for the Sage Creek Pipeline project in Rawlins.
House Bill 117, the Omnibus Water Bill, was passed by the Wyoming Senate Committee of the Whole on Monday and will be debated on the Senate floor at a later date.
