Three times in March, Jack Steck turned on the gas-fueled generator that sent a stream of tiny silver iodide particles rising into a cloud-covered sky over the Sanpete Valley.
He was one of six Sanpete County operators, stationed at strategic locations, who participated this past winter in the ongoing assault against a four-year drought. Other operators stationed between Nephi, on the north, and Hurricane, on the south, joined in the cloud-milking campaign.Did the effort increase the snowpack on the mountain watersheds?
Steck thinks so.
Water conservation districts also think so. They've been giving financial support to the program for more than a dozen years.
Irrigators in Utah counties to the east of the central Utah corridor evidently think so, too. They've complained to state officials that it has taken water from them.
Don Griffith, vice president of North American Weather Consultants Inc., said his firm has analyzed precipitation data gathered from the area east of the central Utah target area. The data indicate increases in precipitation in these downwind areas as well, Griffith said.
The firm also has a contract for cloud-seeding programs in other mountainous areas of Utah. They include the ski areas and watersheds serving Salt Lake City, the Provo River drainage of the western Uinta Mountains, the Stansbury and Oquirrh Mountains, mountainous portions of Box Elder, Cache and Rich counties and the LaSal and Abajo Mountains in southeastern Utah.
North American, which has had the contract for several years, believes it has the hard evidence that proves the program's value. That evidence isn't in yet for the 1990 water year, although the March storms did deliver more than the long-time average amount of water for the wettest month of the year to Sanpete Valley watersheds.
In the Sanpete County area where the seeding took place in December 1988 through March 1989, there was an increase of 5 percent - or .57 of an inch - over natural precipitation, according to the company's data. And over a 12-year period, that's an even more favorable 1.19-inch average increase per season.
"The intent of the Utah seeding program," officials say, "is to increase winter precipitation."
And that, Steck says, "is where we want it, in storage in the snowpack."
That's why he's glad to get the go-ahead from the company's meteorologist in Salt Lake City to open up the valve on the propane tank and put a lighted match to the stream of gas in the generator.
Soon the silver iodide particles are caught up in the storm winds. They interact with the storm clouds, forming additional snowflakes that fall onto the mountain barriers of the intended target area.
Steck doesn't profess to understand the science. It's the meteorologists' job to pick the place and the time and give him a telephone call.
But he's glad to have a hand in the operation. "I live here, too," he says, "and a field of shriveled corn or wheat isn't a pretty sight."