'Notice of Intent to Modify the Weather:' Colorado River basin desperate

In 2020 University of Wyoming researchers learned that seeding clouds with silver iodide did increase snowfall about ten percent in some experiments but has failed to reduce drought conditions. 

Western Weather Consultants has been shooting stuff, including silver iodide, from the ground into the atmosphere over Colorado for some twenty years. Now, Colorado is the driest it has been since 1872.

William R. Cotton is Professor Emeritus of Meteorology at Colorado State University. He says the practice can produce minimal results in winter but summertime seeding is probably fruitless.

“We typically like to say, on an average storm, we can increase it 8% to 12% of the snow-water equivalent,” said Andrew Rickert, weather modification program manager for the Colorado Water Conservation Board. For perspective, federal officials have warned the seven Colorado River Basin states need to find 2 million to 4 million acre-feet of cuts to water use for 2023 because of drought soaking up historic river flows. “Notice to Modify Weather?” Some don’t notice. The “sometimes desperate” search for water in the West is understandable, but “might not be as promising as people wish” in delivering extra snowpack, Cotton has written for science websites. Any “new” water from cloud seeding accrues to the benefit of water rights holders from that basin who, because of drought or holding a more junior appropriation, have lately been right on the cusp of losing their full share. [Is cloud seeding a potential solution to Colorado’s drought?]

Daniel Swain is a climate scientist at UCLA and with the National Center for Atmospheric Research. He says the 3-5% bumps in water that weather modification squeezes from clouds isn't worth the gamble with water equity. Nevertheless, North Dakota conducts geoengineering exercises in parts of that state every year ostensibly to reduce hail damage and enhance rainfall potential.

Arizona draws a third of its surface water from the Colorado. [Is drought in Arizona and the Southwest the new normal?]

Now, in parts of the Southwest some authorities are so fearful of deficits in water supplies they have entertained Durango, Colorado-based Western Weather Consultants' pitch to acquire a “weather control and precipitation enhancement license" from the New Mexico Interstate Stream Commission but after criticism for not consulting with pueblos the application was withdrawn.