WMOD00594

• Title: Investigations of Winter Mountain Storms in Utah during the 1987 Utah/NOAA Field Program
• Date: 1/1/1990
• State: UT
• Weather Modification - Doc Type: Report

delivered to clouds from ground generators less than 50% of the

time, but that there was probably some benefit in locating the

ground generators at high elevations on upwind slopes rather than

in upwind valleys. The implication that seeding from operational
generators may be only partially successful, possibly lead to the

failure to find substantial silver content in snow cores taken in

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the Tushar Mtns during the 1983 season. It was shown that each snow
sample likely contained a substantial portion of unseeded snow, thus
reducing the likelihood of finding evidence that silver entered into

the precipitation process.

The major research objectives in 1987 were very similar to

those in 1983 and 1985. They were:

1) to gain additional understanding of the transport of

silver iodide seeding material from potential ground-based
generators sited west of the Tushar Mtns to clouds upwind

and over the mountains,

2) to increase knowledge of the spatial and temporal

distributions of supercooled liquid water within clouds

over the mountains and of the controlling meteorological

factors, and

3) to increase knowledge of the precipi tat ion processes,
precipitation trajectories, and precipitation efficiency

of the clouds.

Achievement of these research objectives will directly support,
or lead to improvements in, the hypothesis used in seeding winter

clouds in utah for snowfall augmentation. Quoting from Swart and

Griffith (1983), the hypothesis is:

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