Experiment thwarted

Bad weather and red tape blamed for delay

Jim Erickson, Rocky Mountain News

Published March 10, 2007 at midnight

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Bureaucratic hang-ups and unfavorable weather delayed the start of an experiment to see if cloud seeding can significantly boost snowfall in the Wyoming mountains and to help resolve the issue of whether the process really works.

Seventeen ground-based silver iodide generators have been placed in three Wyoming mountain ranges for the five- year experiment.

An airplane with wing- mounted silver iodide flares also is used.

The research team had hoped to fire up the generators by Nov. 15, but the start date on the $8.8 million project was pushed back to Jan. 4, said Bruce Boe of Weather Modification Inc., the North Dakota company hired to seed storm clouds in the target areas.

So far this season, 17 ground-based seeding applications have been performed, along with two airborne events - far fewer than researchers had hoped for, Boe said.

"We missed about six weeks, so we're obviously on the short side this year," Boe said.

Effectiveness debated

Scientists at the National Center for Atmospheric Research in Boulder designed and are overseeing the experiment, which is funded by the state of Wyoming. It started last year with the collection of baseline weather data - but no seeding - at sites in the Wind River, Medicine Bow and Sierra Madre mountain ranges.

Western states spend millions of dollars each year seeding clouds with silver iodide to increase snow or rain. But about 60 years after the first cloud-seeding demonstration, no one knows for sure how well it works.

In 2003, the National Academy of Sciences concluded that "scientifically acceptable proof for significant seeding effects has not been achieved."

The Wyoming Weather Modification Pilot Project is designed to help resolve the issue.

"Hopefully, we'll be able to collect enough of the right data to provide a definitive conclusion as to whether cloud seeding is a viable tool for water resource management in Wyoming," said Dan Breed, the lead NCAR scientist on the project.

Wyoming officials say that even a 10 percent increase in snowpack would provide additional spring runoff valued at $2.4 million to $4.9 million each year.

According to the U.S. Drought Monitor, nearly three-quarters of Wyoming is currently suffering from "extreme" or "severe" drought.

Climate models say the West is likely to warm several degrees by the end of the century. Mountain snowpacks will likely shrink, and Western droughts could become more common and more intense, according to some climate researchers.

Delay tied to permits

This winter's seeding experiments started later than expected because of delays in getting special-use permits from the U.S. Forest Service, Boe said.

Once the permits were in hand, fall snowstorms made it tough to get the silver iodide generators to their remote mountain sites. Some had to be hauled in on snowmobiles, he said.

The fall storms were followed by a drier-than-normal winter, which provided few seeding opportunities. More recently, the weather has been too warm for optimal seeding, he said.

The generators burn a silver iodide and acetone solution, creating plumes of tiny particles aimed at storm clouds approaching mountain summits.

Silver iodide specks attract the cloud's liquid water, which freezes to them to form ice crystals that grow into snowflakes.

ericksonj@RockyMountainNews.com or 303-954-5129

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