Study questions cloud seeding; Sierra researchers defend it

Tuesday, Oct. 14, 2003 | 3:53 a.m.

REGIONAL ED: Attribute to nvren

RENO, Nev.- Nevada's Desert Research Institute is taking issue with a new national study that questions the value of seeding clouds.

The National Academy of Sciences concluded there's little proven evidence to justify the millions of dollars spent by 10 states and dozens of cities to try to increase precipitation by seeding clouds.

"To some extent weather modification is an act of faith with people," said panel member Robert Serafin, president emeritus of the National Center for Atmospheric Research in Boulder, Colo. "In terms of precipitation on the ground, there's no compelling evidence."

But DRI scientists say the study appears to focus on summertime seeding of thunderstorms. They say they have proof that seeding the Sierra helps increase snowfall in the winter.

Meteorologists seed clouds, usually with silver iodide, in an attempt to release more rain and snow. The substance can be released from airplanes or mountaintop generators.

In Nevada, the cloud-seeding program is in its 42nd year. Cloud-seeding generators operate near Elko, in the Tahoe Basin, the Walker Basin and the Toiyabe Mountains of Central Nevada. Last month, the Nevada Legislature's Interim Finance Committee released $479,482, covering the majority of the program's cost for the coming winter.

Arlen Huggins, director of DRIs cloud-seeding program, estimates the program yielded about 80,000 acre-feet of extra water last year throughout Nevada. An acre-foot can supply a family of four for a year.

"I think it has an important role," Huggins told the Reno Gazette-Journal.

"You can get an effect in a target area and the increases in water are significant to the overall supply of water in a snowpack."

Huggins said he is encouraged that the National Academy of Sciences has urged the start of a national research program into weather modification. Thats something scientists at DRI have been pushing for, Huggins said.

The American Meteorological Societys official position is that there has been some statistical evidence showing a 10 percent increase in precipitation after cloud seeding, but no conclusive cause and effect. Cloud seeding is not an effective way to end drought, the society said.

Huggins agrees, saying cloud-seeding is most efficient in boosting precipitation during normal or above-normal years for snow and rain.

In addition to Nevada, cloud-seeding programs are used in California, Texas, Kansas, Oklahoma, North Dakota, Colorado, Wyoming, Idaho and Utah. China spends $40 million a year on it.

The Desert Research Institute is an independent arm of the state's university system.

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On the Net:

National Academy of Sciences: http://www.national-academies.org

Desert Research Institute: http://www.dri.edu/

Information from: Reno Gazette-Journal