Sidebar by Allen Best
Cloud-Seeding – April 2004 – Colorado Central Magazine
Are cloud seeders stealing your water?
No, say scientists, but legal issues of cloud seeding are not yet sorted out.
One of the most frequent questions asked about cloud-seeding programs is whether, by drawing extra moisture from storms, areas downwind will be deprived of precipitation that should be theirs. Or, as the website for North American Weather Consultants puts it: Does cloud seeding rob Peter to pay Paul?
Atmospheric scientists say it doesn’t. Cloud seeding typically increases snowfall by less than 20 percent. Furthermore, especially when cumuliform clouds are present and over mountainous terrain where air is forced to rise, the cloud-bearing layer of the atmosphere undergoes nearly continuous moisture replenishment, says the company website. And increased snow pack can extend, albeit in small quantities, for up to 100 miles downwind of the targeted areas.
Grant and his team studied the issue of downwind effects from the Climax seeding experiments in the 1960s. They found no indication of reduced downwind precipitation. However, they found some indication of increases in precipitation downwind.
Another study conducted by Grant and his team looked into the possibility of a downwind effect in Wyoming from Utah’s extensive cloud seeding. It was concluded that there was little or no statistically significant effect, although again there were some indications of a slight increase in precipitation in the downwind area.
Kansas, for a time, complained that cloud seeding in Colorado was depriving Kansas of precipitation through its cloud seeding, says Joe Bustos, who administers the weather modification permitting program on behalf of the Colorado state government. But Kansas also tries to seed clouds, he notes. “It’s kind of hard to sue people for using technology that you are also using.”
This can cut both ways, of course. At Leadville in the late 1980s, residents complained they were being forced to endure snowfall intended by cloud seeders for Vail. Steamboat-area ranchers in the 1970s griped of the extra feed they had to buy to feed cattle.
These complaints have never been pushed into the courts for resolution. The State of Colorado, in a webpage document, says simply that the state program has made it a top priority to seek out all of the hidden costs in cloud seeding. It may take years before the full effects of cloud seeding are known.
–A.B.
