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based upon analysis of precipitation in areas downwind ofrcsearch and operationally oricnted cloud seeding programs. In a revicw paper on this topic. Long (2001) provides information from a variety of both wintcr and summer programs. One wintcr research program that is pcrhaps most rclevant to \\'inter timc programs was one conductcd by Colorado State University scientists in the Climax. Colorado area. This area is located in a mountainous area located in the Central Colorado Rockies. This randomized seeding program was conducted in two phases that came to be known as Climax I and Climax II. Quoting from long (2001). "Janssen. Meltsen and Grant (1974) investigated dowm....ind effccts of the Climax 1 and II projects. They noted that their investigation was post hoc and as such was exploratory rather than confirmatory. In order to dcteet downwind precipitation effects drifting from the Climax target area various time lags ranging from 3 to 187 hours of precipitation data from hourly stations in dowmvind locales were considered. Significant ratios of seeded to not-seeded precipitation. with low probabilities of being due to chance. were found downwind east and northeast of the Climax area. These ratios were in the range of 1.15 to 1.25 during the 3-12 hour time lag period:' This suggests increases in prccipitation on the order of 15-25% dowm....ind of the intended target area. Long (2001) provides a summary statement in his paper as follows: "Dowmvind precipitation cffeets have been observed in gcographic areas anu time frames that arc about the same magnitudc as primary effects intcnued for the target area. There is little evidence ofa decrease in prccipitation outside the target area:' An cxample of an analysis of potential dowm....ind effects from an operational wintcr program is found in Solak et al. 2003. This paper examined the precipitation that fell in areas located in eastern and southeastern Utah and western Colorado located downwind of a long-term winter program that has bcen conducted most \....imers sincc 1974 in the central and southcrn Wasatch Moulltains of Utah. The abstract from this papcr is as follows: "Estimations of cffccts on precipitation downwind of a long-standing operational snowpack augmentation project in Utah arc made. using all adaptation of the historical target/control rcgression technique which has been ust:d to estimate the seasonal effccts over morc than twcnty scasons within the project's targct area. Target area analyses of Dect:mber-March high clevation prccipitation data for this project indicate an overall scason-average increase of about 14%. Thc downwind analyses indicate increases of similar magnitude to thosc for the targct...extcnding to about 100 miles downwind." Toxicity of Scedine Al!cnls By far the most common seeding agent in usc today on wintcr orographic cloud seeding programs is silver iodide. The potential cnvironmcntal impacts of silver iodide have been studied cxtensively. Klein (1978) in a book entitled "Environmental Impacts of Artificiallcc Nucleating Agents" concludes that '"The major environmental concerns about nucleating agents (cffects on plant growth. game animals. and fish. t:te.) appear to represent ncgligible environmental hazards. The more subtle potential effects of silver-based nucleating agents. sllch as thcir possible ability to potentiate the movcment or cffects of other materials of environmental conct:m. or to inlluenee thc activity of microorganisms in soils and aquatic environments after being bioconcentrated by plants. warrant continued research and monitoring. Effects. if they occur. arc not expected to involve unacceptable risks. The long~tcnn lISC of silvcr iodidc and the confidence which the weather modification profession has in dclivery systems and in the efficacy of this