Monday, June 24, 1996

Parched Texans Turn to Science for Rain

By Associated Press

DALLAS (AP) - When the wait for rain becomes intolerable, drought-ravaged farmers turn to a different type of planting: They hire a team of weather scientists and daredevil pilots to seed clouds.

"This is an operation when you want to have your wits about you," said Tony Grainger, a cloud physicist from the University of North Dakota.

"It's not like flying in an airliner. It's pretty much shake and bake," he told The Dallas Morning News.

Grainger searches radar screens and computerized weather data for developing cloud systems ripe with moisture. When the weather is just right - whether morning, noon or night - he dispatches a pilot from the motor home from which he works to an aircraft hangar 500 yards away.

Within minutes, the twin-engine airplane heads toward the thunderstorm. Grainger guides the pilot to the cloud's most promising tops by two-way radio.

"With radar, you have a pretty good idea of where you are at," said Mark Rivard, one of the cloud-seeding pilots. "The new growth where the cloud tops are forming is where we hang out at."

The airplane is equipped with a flare launcher and flares that produce a smoke containing microscopic silver iodide particles. The particles attach themselves to partially frozen water droplets.

At the right moment, usually between at 18,000 to 20,000 feet, the pilot fires the flares into the clouds.

Grainger leads the cloud-seeding team - himself, pilots and an electronics engineer - from the Weather Modification Inc. of Fargo, N.D.

The newly-formed West Texas Weather Modification Association, a group of farmers and ranchers in the San Angelo area, has hired the team to seed clouds over a 6 million-acre area of cotton farms, cattle and sheep ranches and recreational leases.

Critics have accused cloud seeders of creating flood and hailstorms. Others say the operation causes clouds to rain early, robbing downwind land owners of moisture.

George Bomas, a meteorologist with Texas Natural Resource Conservation Commission, disagrees. His agency issues permits and monitors cloud-seeding components operating in Texas.

"We've never seen a seeded system be a hail producer or produce winds or tornadoes of flash floods," he said.

Last week, the Alamo Area Council of Governments - representing 90 local governments from 12 South Texas counties - voted to seek bids to seed clouds in their areas.