U.S. Water News Online
MANHATTAN, Kan. -- In wide-open western Kansas, rain and hail are serious business with an impact on every wallet. But attempts to alter such weather are meeting increasing controversy.
Nay-sayers think past attempts to reduce hail damage have limited vital rainfall. Yea-sayers believe history has shown cloud seeding brings sizeable benefits.
Recent research at Kansas State University indicates, however, the facts aren't clear-cut. So far, no one can truly measure what happens when humans try to interject a kick in weather's get-along.
Since 1975, the Western Kansas Weather Modification Program (WKWMP) has been seeding clouds to suppress hail and promote rain in southwestern Kansas. In 1997, the program expanded into northwest Kansas and became the largest aviation-based cloud-seeding program of its kind in the nation.
Roughly 55 percent of last year's WKWMP funding came from individual counties and groundwater management districts in western Kansas. The balance came from the state.
By 1998, however, northwest Kansas had a new group -- the Concerned Citizens for Natural Weather -- organized to formally oppose cloud seeding.
"Given what's known now, neither side in the debate is right ... or wrong ... or likely to change its mind," said K-State Research and Extension economist Terry Kastens. "Opponents have some scientific backing for their anti-seeding stance, but an equal amount of research refutes their claims."
The modern science of weather modification emerged shortly after World War II. It was an offshoot of General Electric's attempts to prevent icing on aircraft wings.
"Science got promising results in the lab. Its results were more ambiguous when applying the technology to actual clouds," said Brian Vulgamore, who conducted K-State's study as part of his graduate degree program and now farms near Scott City, Kan. "Unfortunately, science was unable to separate fact from fiction after that, due to lack of research funding in the 1980s and '90s."
That's why his study bypassed the science of modifying the weather. Instead, Vulgamore tried to assess real-life impacts. He examined both rainfall and hail in western Kansas and worked to put their outcomes in dollar terms.
"The smallest drought causes economic harm in any semi-arid farming region," Kastens pointed out. "Up to a point, extra rainfall brings extra economic benefits."
But equal precipitation losses and gains don't bring equal results. Vulgamore's analyses suggest that an added inch of growing-season rain in western Kansas translates into an economic gain of about $18 million. A 1-inch loss in rainfall translates into economic losses exceeding $19 million.
Even so, this finding provided little insight, because the study also revealed:
"This doesn't mean the WKWMP hasn't had an economically significant impact on the moisture supply. It merely demonstrates the difficulty in measuring impacts of this kind. Statistics couldn't prove undeniable results because western Kansas naturally has widely variable weather," Vulgamore said.
To assess the other half of the WKWMP mission, K-State's study looked at the dollar losses of hail-damaged crops. Vulgamore compared every western Kansas county's long-term loss average with its average for the cloud-seeding period.
He found that while the WKWMP was at work, individual counties within the program's target area had seen significant drops in hail-related damage. Many counties east of the target area also had recorded sizeable damage declines, suggesting a possible downwind effect. Yet, several Kansas counties north and south of the target area saw large damage cutbacks, too.
Vulgamore then grouped the counties by whether they'd participated in the program. He found that on average, the target area counties had shown a 15 percent greater drop in hail-related crop loss.
"Keeping that 15 percent in perspective is important," Kastens said. "Given the wide variability in western Kansas weather, the difference between the target and non-target counties could have been a matter of normal, natural hail patterns. Besides, we can't say with statistical confidence that the WKWMP is responsible for the 15-percent drop. The WKWMP would have had to reduce hail damage by nearly 60 percent before statistics could say the change pointed straight to cloud seeding as a cause.
"Even so, Brian's analyses indicate that if the WKWMP reduced yield losses by 3.5 percent, it paid for its own program costs. In fact, if you consider the hail damage of buildings, equipment and other property, the amount of saved crop yield needed to make the program pay would be even less."
On the whole, Vulgamore is optimistic about the potential for weather modification.
"Although assessing its effects with confidence will require much more research by physical scientists, I would hate to completely shut the door on this technology," he said. "I believe the most promising aspect of weather modification is its relatively small cost, compared to the potential return."
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