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<br />. <br />. <br />~ <br />~ <br />~ <br />~ <br />~ <br />. <br />~ <br />~ <br />. <br />~ <br />~ <br />I <br />~ <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br /> <br />The p.-ecipitation e,'aluation discussed in section 4.IA indicated a seeding effect of 3- <br />4%. The soo" "ate.- content naluation (section 4.2.2) suggested a larger effect. approximately <br />a 13-14% increase. It is unclear why the indicated increases in precipitation are less than those <br />indicated in the snow water contents. It is noted that a similar result was indicated last year. <br />!\A WC's report for last year indicated a potential problem in the precipitation measurements <br />related to under catch of snowfall due to strong winds at the near to above timberline S~OTEL <br />sites in the target area. Examination of the plots of precipitation and snow water content from <br />this past season did not seem to indicate such an effect. <br /> <br />As discussed previously. in the evaluation of only one or two winter seasons of seeding it <br />is difficult to attach much significance to the results to unless the correlation coefficient between <br />target and control areas is extremely high (e.g. > 0.95) and the indicated effects of seeding are <br />quite large (perhaps> 20%). Normally. several seasons of seeding are necessary to establish <br />confidence in the indications of seeding effects. Also. the potential impacts on the Gunnison <br />County evaluation from seeding programs (both current and historical) over the Grand Mesa and <br />West Elk Mountains are unknown. but are likely causing an under-estimate ofthc actual seeding <br />effects in the Gunnison target area. <br /> <br />-4.5 Potential Seedine Impacts at the Rock,. \Iountain Rioloeical Lahonton <br /> <br />One of the requirements of the original 2002-2003 cloud seeding pemlit received from <br />the State of Colorado was to attempt to estimate the impact of the seeding project upon <br />precipitation received at the Rocky \1ountain Biological Laboratory located at Gothic. Colorado, <br />which is approximately 5 miles north of Crested Butte. \\'e searched for historical and current <br />observations of precipitation that might be used to develop a historical target/control analysis <br />such as that developed for the overall target area. We considered records from Crested Butte. a <br />long-term ~ational Weather Seryice cooperati\'e station. although this site was outside the <br />intended target area. We plotted the records from Crested Butte against Buena Vista (a site with <br />a good historical record) in the double-mass format described previously in this report. The <br />resuil is provided in Figure ~.13. Unfortunately. a discontinuity in the data is indicated by the <br />plot and we therefore did not consider this site any further. There is another precipitation <br /> <br />. <br />I <br />I <br />I <br /> <br />55 <br />