Can 'Weather Modification' Help In A Drought?

October 6, 2011 5:00 am by: Matt Largey

Texas could remain in the grip of the current drought until 2020. The drought could surpass the so-called "drought of record" that happened back in the 1940s and 50s.

That drought spawned some scientific approaches to what's become known as "rainfall enhancement" or "weather modification".

And some have wondered why we can't just use the power of science to make it rain in this drought.

Whenever I think about weather control, I think about G.I. Joe. There was an episode where one of the bad guys builds a weather machine. Turns out, it's not just for super-villains.

"It's not science fiction," said John Nielsen-Gammon, the state's climatologist. "About a third of the state of Texas has contracts with weather modification companies to engage in cloud seeding on an annual basis."

Right now, cloud seeding can't make rain. But there is evidence it can make it rain 5, 10, 15 percent more.

"The problem with that, in a drought, is 10 percent of nothing is nothing," said Nielsen-Gammon.

The first thing you need for cloud seeding is a cloud, but not just any cloud. You need the right kind of cloud: a thunder cloud.

"Many of the young thunderstorms that develop in Texas skies have a wealth of cloud water; many, many trillions of tiny droplets," said George Bomar, who runs the weather modification program at the Texas Department of Licensing and Regulation.

But Bomar said those droplets don't necessarily come together all the time.

"The way Mother Nature grows large raindrops quickly is by providing many of these thunderstorms with an abundance of ice nuclei – very tiny ice crystals," said Bomar.

Cloud seeding puts more of those nuclei in the cloud. To do that, you need a plane. Pilot Craig Funke has seeded clouds for years in South Texas. He flies around the cloud and set off flares that send out silver iodide.

"It's a trigger mechanism to cause that water to freeze," said Funke. "Instead of all these super-cooled water droplets floating around this cloud, it freezes and the water attracts and freezes to that frozen drop."

"So by inserting ice crystals, you speed up the process of growing a tiny cloud droplet into a rain droplet, which can then collide with neighboring droplets," added Bomar.

When those droplets become drops, they fall out of the cloud as rain.

"Unfortunately, it's most effective when you need it least, and it's least effective when you need it most," said state climatologist Neilson-Gammon.

Seeding works well during normal, wetter weather patterns, but is less effective in a drought. There just aren't enough of the right storm clouds.

There are new techniques out there like salt crystals ground down to teeny, tiny particles. Swiss scientists say they can make rain with lasers. But finding the money for research is tough.

George Bomar says the local water districts should be developing and refining these capabilities even when they're not needed "and then, when you go through the next drought cycle, you're going to be in a lot better shape. You're going to have more water in your aquifers and in your surface reservoirs, and it'll last you longer in middle of an exceptional drought."

There are of course concerns that making it rain more in one place, means it rains less somewhere else. Bomar says there's little evidence that that's the case. But those concerns are still out there, and there's a lot that's not known about how complex weather systems work.

Take China for example.

The government there has a well-funded and well-known weather control effort. They may have gotten more than they bargained for a few years ago. A storm reported to be a target of cloud seeding dumped the heaviest snow in decades and caused almost half a billion dollars in damage.

Even a super-villain would be awed by that.

Source: KUT