Drought-Ridden Oklahoma Seeks Relief From High-Tech Rainmakers

The Rev. Wesley Peterman urges his parishioners to look only to God in their search for rain. But some farmers in parched northwestern Oklahoma also are looking to the heavens--for the silvery glint of airplanes.

The state’s hiring of pilots to coax rain from passing clouds troubles the Laverne pastor and farmer whose own wheat crops withered in dusty fields.

“I believe you’re messing with God’s plan,” Peterman says. “I think it would be best to leave it alone.”

He adds, “I’m also not sold on it.”

Scientists also are not convinced that cloud-seeding is the answer to nearly a year of extreme drought. But with 10% of Oklahoma’s producers facing bankruptcy or leaving farming because of crop failure--and more rainless days forecast for coming months--state leaders were willing to gamble.

They withdrew $1 million from the state’s reserve fund in hopes that cloud-seeding would bring some rain. The experts warned Gov. Frank Keating it might not work, but he said he believed that it was worth trying.

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An unusually wet July has helped ease severe or extreme drought conditions in some portions of the state. but northeastern Oklahoma has received only 18 inches of rainfall since last Oct. 1; that’s about 14 inches below normal. The state has averaged nearly 22 inches of rain for the same period--about 6 inches below normal.

States--including Texas, Kansas and North Dakota--have used cloud-seeding for more than two decades. Experts acknowledge that pinpointing when to seed and measuring how much rainfall is created can be difficult.

Cloud-seeding, for example, has been performed for 25 years near Big Spring, Texas, about 270 miles west of Dallas. Meteorologist George Bomar, of the Texas Natural Resource Conservation Commission, is convinced it works.

“There has been a 25% to 35% increase to average seasonal rainfall where seeding has been done and significant increases in areas downwind,” Bomar said.

Cotton-crop yields in counties where seeding is done have increased an average of 40% to 60%, although that doesn’t account for any technological advances, he said.

Cloud-seeding also has been used for decades in Kansas and North Dakota, primarily to suppress hail.

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Patrick Sweeney, president of Fargo, N.D.-based Weather Modification Inc., reports a 45% reduction in crop-damaging hail because of seeding.

He says his company, which Oklahoma hired for $801,000 to begin cloud-seeding in August, typically can squeeze 15% more rainfall out of passing clouds.

But, he warns, cloud-seeding is no cure for the cloudless days associated with drought. Rain clouds must be present for pilots to release the microscopic particles aimed at triggering raindrop development.

“Cloud-seeding doesn’t create clouds; it increases the efficiency of clouds,” Sweeney says.

The process works best over a period of several years, the experts say. It offers no quick-fix solution to drought emergencies.

“Never wait until you’re in a drought to begin using cloud-seeding,” says Bomar, the Texas meteorologist. “Obviously for cloud-seeding to be effective you have to have clouds--and not just any cloud will do.”

Jerry Straka, a University of Oklahoma professor who studies severe weather, cites a lack of independent research on cloud-seeding and warned legislators last spring that the project could fail.

“We know that it does work some of the time, but we can’t guess which cloud is the cloud we can enhance precipitation from,” he said.

Straka plans to study the results of the Oklahoma seeding project. The pilots will continue seeding through October and resume next spring after a winter break.

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Cloud-seeders say theirs is a precision craft, requiring exact timing in perfect cloud conditions.

The pilots release flares containing microscopic silver iodide particles, a compound that mimics the structure of ice. The particles give droplets of supercooled water in the clouds something to grab onto and form ice crystals that fall to earth in the form of raindrops.

One of the state’s top consultants in weather modification has no doubt cloud-seeding can enhance rainfall. But Ray Booker, founder of Tulsa-based Aeromet, warns that it can go too far.

About a three-minute window exists when a cloud is prime for seeding, he says. Seed too much and the cloud may become jammed by forming ice crystals.

“Finally, you get an ice cloud that just floats away,” says Booker, a cloud physicist and former commercial cloud-seeder whose company now specializes in studying clouds for the military.

He says a good cloud-seeding program needs to be scientifically based, used as a long-term water-management plan instead of emergency relief, and have a system in place to objectively measure the results.

The state, he says, is going about it all the wrong way.

“It gets people’s hopes all blown out of proportion. People in Oklahoma are frankly suffering greatly. . . . You get cloud-seeders coming in, pumping up hopes. You get the idea cloud-seeding can do something to save them, and they cannot do it.”

Meteorologists at the Oklahoma Climatological Survey, a state entity operated at the University of Oklahoma, are charged with analyzing Oklahoma’s project, but Booker says the cloud-seeders would have to seed some clouds and fire blanks into others to get objective measurements.

Harold Springer, chief engineer of the Oklahoma Water Resources Board, admits not as much money has been set aside for data collection as he would like. But he believes the project can help replenish the state’s depleted ponds and reservoirs.

For farmers whose hopes rise and fall with each passing cloud, the prospect of seeding the clouds offers new hope.

In the town of Laverne, the pastor of the First United Methodist Church doesn’t see any moral dilemmas in that.

“I think we have to be good stewards of nature and make sure it doesn’t have any adverse reactions,” said the Rev. Gary Holdeman. “But just the fact of seeding--I don’t see anything wrong with that at all.”

But, at the First Assembly of God, Peterman finds the moral questions as burning as the scientific ones.

He and his brother harvested only about one-third of their normal wheat crop, but he thinks that the state would be better off saving its money and leaving the clouds to God.

He knows many of his fellow farmers don’t necessarily agree.

“I know there’s probably a lot of them questioning, ‘Lord, why hasn’t it rained?’ ” he said. “But we realize we can’t control it. We have to leave that in the hands of the Lord.”