WMOD00011

• Applicant: Don Griffith North American Weather Consultants, Inc.
• Sponsor Name: City and County of Gunnison
• Project Name: Cloud Seeding Evaluation
• Title: The Development, Conduct and Evaluation of a Cloud Seeding Program for the Gunnison River Basin, Colorado During the 2003-2004 Season
• Prepared For: City and County of Gunnison
• Prepared By: North American Weather Consultants
• Date: 8/1/2004
• County: Gunnison
• Weather Modification - Doc Type: Report

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observation site at Gothic maintained by the Environmental Protection Agency. Unfortunately,
records from this site only dale hack to 1989. We considered this to be too short a record for the
establishment of a reliable historical regression equation. especially since some of the available
years of data would need to be excluded due to concerns about contamination from other earlier
cloud seeding projects. It is our understanding that there are special snow observations made at
Gothic by a local resident. Billy Barr. possibly dating back to 197~. These observations do not
appear as official records available from any State or Federal agency. There is another
complication in any attempt to evaluate the impacts of this cloud seeding program upon the
Rocky ~ounlain Biological Laboratory. This complication arises due to the fact that operational
cloud seeding programs have been conducted over portions of the Grand :vtesa and \Vest Elk
Mountains over approximately 31 winter seasons prior to the 2002-2003 winter season. It is
very likely thai these programs have impacted the precipitation at the laboratory (i.e. dov,"nwind
seeding effects). We have not attempted to document the magnitude of these effects.

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Figurt" ~.13 Prt"cipitation at Crt"stt"d Bultt" \"S. BUt"na Vista

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