As Storms Arrive, Rainmakers Are Still in Demand

It can rain and it can pour, but some California cities still want more of the wet stuff.

Even with a big storm already pounding the coastline, some communities scattered up and down California fear that El Nino won’t deliver.

So, despite Friday’s El Nino-driven drenching, it seems that behind the next gray cloud there could be a lining of, well, silver iodide.

Water districts in about a dozen communities from Salinas to Bakersfield to Santa Barbara have contracted with a professional rainmaker to seed clouds in an attempt to increase precipitation this winter and bolster water supplies.

Even the Los Angeles Department of Water and Power is seeding clouds in the Sierra Nevada.

While hiring rainmakers in the face of El Nino may sound like a case of selling ice to the Eskimos, local officials want to be prepared in the event that the much-talked-about meteorological phenomenon does not produce adequate levels of water for storage.

“A quarter of all El Nino years turn out to produce below-average rainfall,” said Dennis Gibbs, hydrologist for the Santa Barbara County Water Agency. “Cloud-seeding is very cost-efficient water management,” he said.

Cloud-seeding is the process of spraying water-packed clouds, usually by airplane or from flares off the ground, with silver iodide crystals. The crystals form ice droplets, which produce extra snow or precipitation.

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Concerned each year by the potential of drought and water shortages, the Santa Barbara County Board of Supervisors has voted to implement a cloud-seeding program that will begin Jan. 1. It will cost the county $216,000--cheaper, officials say, than buying water from state agencies.

“We still don’t know how El Nino works,” said Robert Almy, manager for the Santa Barbara County Water Agency.

Almy said there is a misconception about cloud-seeding during El Nino seasons--that it will produce too much rain and, ultimately, floods.

But without the right kinds of rain clouds and perfect timing, the process of cloud seeding does not work, he said. And even then, the average rainfall may only increase 3%.

“When we are in a drought, cloud-seeding has no effect,” he said. During some significant El Nino years, the county actually had inadequate rainfall.

“We’ve concluded that while in 1982 and 1983 [California] had a much higher than normal rainfall, [locally] we only got moderate storms” that brought low rainfall averages to the county, Almy said.

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“To us, El Nino is a significant weather phenomenon because we rely very heavily on local water supplies,” he said. “We are being cautious, and prudent and in a position to maximize benefits.”

In Visalia, Bruce George, manager for the Kaweah Delta Water Conservation District, said, “History has shown us that nobody has been able to forecast from a year ahead, here in the Central Valley at least.” In that valley, he said, “there have been many years we had a wet November and then a dry year.”

George said there have been times when the valley was flooded one month and cloud-seeding was suspended, only for the rest of the season to be dry. In those years, he said, it would have been better if they had continued cloud-seeding.

Producing too much water and even floods remains a concern among environmental activists and mountain residents, hydrologists say.

Two decades ago, numerous lawsuits were filed against Los Angeles County by some who claimed that cloud-seeding above the San Gabriel Mountains intensified a major storm that killed 11 people and caused $43 million in property damage. The county prevailed in each of the suits.

State Department of Water Resources hydrologist Maurice Roos said that while cloud-seeding enhances precipitation, there is no “hard evidence on how much cloud-seeding really yields.”

“The tricky thing is that early on in the season, you don’t know what’s going to happen.” he said.

Cloud-seeding is already underway over the San Joaquin River between Bakersfield and Fresno. Southern California Edison has funded cloud-seeding over that area since 1950.

It is one of the oldest and longest-running cloud-seeding programs in the world, said Brian McGurty, chief hydrographer for Southern California Edison. The company pays about $300,000 annually on the program.

The additional water is used primarily for the company’s hydroelectric facilities, as well as recreational uses in reservoirs, and irrigation purposes for farmers.

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“We haven’t seen El Nino yet, and it may never happen,” said McGurty, who said that so far “there is no evidence yet that this is a wet El Nino year.”

The Los Angeles DWP has begun cloud-seeding in the eastern Sierra Nevada to feed the Los Angeles Aqueduct. The project’s cost is about $75,000.

“Just because we’ve had a couple of wet months doesn’t mean we’re going to have a wet year,” said Vee Miller, hydraulic engineer for the DWP. Los Angeles County is still recovering from a drought seven years ago, he said. “Right now, it’s so early in the season, we can’t tell what’s going to happen,” Miller said.

And neither can meteorologists--or even Tom Henderson, president of Fresno-based Atmospherics, the largest cloud-seeding company in California.

Henderson said that if El Nino brings more rain than the water districts can handle, all cloud-seeding projects in the state will be suspended.

“Most of these cloud-seeding projects are sponsored by agencies which use this as one more water resource tool,” Henderson said.

A former hydrologist, Henderson founded Atmospherics in 1960. The company has contracts in 12 states and 16 countries.

But should “Mother Nature get the ball rolling” and El Nino does deliver, then cloud-seeding projects in California will halt.

“The threat of a possible El Nino suspends and turns all contracts off,” he said.

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How Seeding Works

Storm clouds are filled with droplets of water that are very cold but don’t freeze. In order to fall, they must form ice crystals by growing extremely cold or attaching themselves to a solid particle. Nature provides such particles in the form of dust. Cloud-seeders coax the process along by injecting silver iodide particles into clouds. The droplets freeze onto these particles, and precipitation begins.