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<br />vast numbers immediately do\tTI\vind of expanded propane hecau.-.e substantial chilling of the air <br />caUSc."S homogeneous nucleation of ice crystals. Propan~ seeding has long been in lL'>e for clearing <br />supercooled liquid water fog at major airports. It has been tcsted experimentally 011 the Sicrra <br />I\evada of Cali fomi a (Re~..nolds 1991. 1996) and on the Wasatch Plateau of ccntral Utah (Super et <br />al. Ilf95). Further experimentation is planned in l;tah during the "intcr of 2003/04. and pmpane <br />St."Cding ofwintcr orographic clouds is still in the dl:velopmcntal stage. <br /> <br />In surnrnat)". the evidcnce presented in this report. both from silvcr-in-snow analyses and <br />from many past investigations. indicatl.."S serious targeting problems \\ith the 2002103 DWB <br />opt:r.Jtional seeding projcct. The evidence strongly suggests that thc Sl."t.-ding approach did not <br />routinely result in transpon and dispersion of adequate conct.'Otrations of AgI into intended cloud <br />regions ov~r the mountains. Physical pl~ tracing and modeling imestigations "ould no doubt <br />provide guidance as to how to improve seeding methodology. Sc..eral past studies have already <br />indicated. however. that the probable solution is to release the SCt.~ing agent from higher a1titudcs <br />up the \It;ndwanl mountain slopes and/or from aircraft. <br /> <br />ACK:-;OWLEDG~IE:-OTS <br /> <br />The authors thank thc Vail and Copper \-10untain ski resorts for provision of sno....-cat <br />transportation to ['.\.'0 of the 10 snow sampling sites within the DWB Sl..--cding target. We thank <br />also Dr. Joe McConnell of DRI for his cooperation in overseeing the [race chemical analyses and <br />Dr. Jim Heimbach for his assistance with Figure 1 <br /> <br />REFERENCES <br /> <br />Amcrican MCk'Orological Si.lCiet~. 1998: Polic~ Statement- Planned and Inad\enent Weather ~1odifkation. <br />Bulle/in ufthe Amerkwl Sode~r. 79. 2771.277:. <br /> <br />Brov.n. M. J. and E. L. Peck. 1962: Reliabilil) of Precipitation Mca.~rements as Related to Exposure. <br />Journal of Applied Meteorolog)'. 1. 203-207. <br /> <br />Brujntj~'s. R. T.. 1999: A Ret-jev. of Cloud Sc.~ing E:qxriments 10 Enhanc~ Precipitation and Some ;..Jev. <br />ProsjXX:ls. Bulle/in American Jfe/eoru/v,.:kv/ Society. SO. 805.820. <br /> <br />Chai. S. K.. W. G. Finnegan and K. L. Pitter. 1993: An Interpretation of the ~techanisms of Ice--Crystal <br />Fonnation Opcrati\'c in the Lake Almanor Cloud-Seeding Program. Journal of Applied .We/euroIOf{l'. <br />32. 1726- 1732. <br /> <br />Dennis. A. S.. 1980: Weather Modirication b\ Cloud Sccdin2,. Academic Press.. :-';e\\ York. SY. 267 pp. <br /> <br />EUiotL R. D.. R. W. ShatTer. A. Court and J. F. Hannaford. 1978: Randomized Cloud Seeding in the San <br />Juan Mountains. Colorado. Journal of Applied Jfe/eurolohov. 17. 129&-1318. <br /> <br />Goodison. RE.. 1978: Accuracy of Canadian Snow Gage ;\.1easuremenlS. Journal of Applied <br />J{eleurolokPo.. 17. 15~:::-15~8. <br /> <br />,- <br />-' <br />