In Colorado, ski-area operators and water managers have been known to do a few rain dances and — privately at least — pray to their own God when drought strikes. But in the age of technology and hubris, when nearly every challenge is met with engineering, they aren’t just waiting for Mother Nature to put her cards on the table. Instead, there’s a growing interest in seeding clouds with silver iodide to coax every possible bit of moisture from passing storms.
Weather modification has historic roots in the Cold War era, when both the U.S. and Soviets looked at ways to weaponize weather, and more recently, U.S. intelligence agencies decided to help fund a far-reaching study aimed at determining if there’s a way to mitigate global warming with technology and engineering.
Proponents have claimed for years that seeding can increase snowfall in targeted areas by as much as 15 percent. As a result, water providers like Denver Water, and big ski resorts, including Vail, Breckenridge and Winter Park, are all helping fund a $1 million cloud-seeding program in Colorado’s north-central mountains, hoping to improve ski conditions, as well as boost stream flows and reservoir storage.
Recent news about record-low flows from Lake Powell, the key Colorado River reservoir, has spurred even more interest in enhancing natural precipitation, said one of the state officials who manages what’s formally called a weather modification program. A roster of companies involved in cloud seeding and related activities shows that weather modification is a growth industry.
The state program is run by the Colorado Water Conservation Board, which issues permits and sets basic rules — for example cloud-seeding stops when the snowpack reaches a certain level to address concerns about avalanches and flooding.
But those rules haven’t quelled concerns, as there are still a few people left who probably think that tinkering with the weather on a large scale is probably one of the worst ideas ever. Those sentiments were reflected during a hearing for cloud seeding permits in the early 2000s. Residents of Evergreen turned up en masse to claim that, ever since Vail started seeding clouds (way back in the 1980s), snowfall in their town has declined.
The CWCB program was jump-started with state seed money in the early 1970s, but since then has become 80 percent – 90 percent self-funded through grants and participation by resorts and water providers, with everyone seeing cloud-seeding as a low-cost alternative to building new reservoirs and pipelines. And with an uncertain outlook for Colorado River flows, even downstream states like Arizona and California are ponying up to help pay for cloud seeding in the headwaters.
The question about downwind impacts seems reasonable. After all, there’s only so much moisture in every cloud. But weather experts like Colorado state climatologist Nolan Doesken say there’s not a shred of evidence to show that cloud-seeding affects snow and rainfall downwind of the specific target areas. The weather pattern most suitable for mountain cloud seeding (a steady, moisture-laden jet stream out of the northwest) generally leave the plains high and dry.
On the other hand, Doesken said there’s no clear evidence to show that seeding enhances snowfall anywhere near the amount claimed.
“If it really increased snowfall by 15 percent, you’d be able to see that in streamflow records from, say, the Gunnison Basin (where seeding has been ongoing for many years), but that’s not the case,” Doesken said. Overall, he believes that seeding does boost precipitation, but by a lesser amount than claimed…
So when your score your first face shots this coming winter, go ahead and enjoy the celebratory bonfire in honor of Ullr, the Norse god of skiing. But just to be on the safe side, don’t forget to raise your glass in a toast the men and women who promise better living — including more snow — through chemistry and engineering.