June 22, 2004
BY LUCIO GUERRERO Staff Reporter
Organizers of a recent Paul McCartney concert in Russia wanted to make sure that he could sing "Good Day Sunshine."
So when clouds began forming over the outdoor concert venue, they decided to take matters into their own hands: They sprayed the clouds with dry ice. The move, called weather modification, cost organizers around $40,000 but it assured Sunday's concert in St. Petersburg would stay dry.
The Russians have used the method before to stop rain from putting a damper on big events. Russian President Vladimir Putin ordered cloud seeding during St. Petersburg's 300th anniversary celebrations.
So can we expect every Taste of Chicago to be dry? How about a sunny Air and Water show?
Probably not.
There hasn't been a weather modification program in Illinois for about 20 years. And those projects included making rain -- not stopping it, as in Russia.
"One of the hardest things is proving that it works," said Stanley A. Changnon, a senior scientist at the Illinois State Water Survey, who worked on weather modification in the 1970s and 1980s. "It's very difficult to evaluate its effectiveness."
Which means, did it rain because of the cloud seeding, or was it just supposed to rain?
Many skiing areas in the West use weather modification to help promote snow on their mountains. Other municipalities use weather modification to help minimize hail storms and to alleviate fog.
The technology used in weather modification is fairly simple.
Planes go over the top of the clouds -- usually about 18,000 feet -- to disperse ice-forming agents such as silver iodide or dry ice. The agent causes icelets to freeze and grow. When they grow, they fall as precipitation.
But what makes the Russian experiment over the McCartney concert unusual is that weather modification was used to chase the rain away.
Mark Solak, vice president of industry-leading North American Weather Consultants Inc., said the Russians may have saturated the cloud with dry ice. That would create so many ice particles that they would be too small to fall.
Although Illinois does not have any active weather modification programs, there is a law on the books regulating it.
"We wanted to make sure that people who did cloud seeding were from quality firms using good equipment," Changnon said. "We don't want anyone flying into a tornado.''
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