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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December 2003

December \vas another fairly nnonnal" weather month for the Gunnison Basin, ",,'jth the
exception of a series of strong storm events near the end of the month. These storms near the
end of December brought snow water content. and even water year precipitation. back 10 normal
or slightly above in some areas. Other areas remained below nonnal as of the end of Decemher.
Five storms were seeded in December.

A frontal system began moving into Colorado on the night of December 7-8. Seeding
began on the evening of December 7 (#4), and continued through most of the glh. The best snow
fell on the morning of December 8. with moderate to heavy snowfall in much of the basin. Snow
tapered ofT to shO\....ers in the afternoon. but seeding continued until about 1700 MST. Up to a
foot or more of snow fell in the target area. with water equivalent of about I" across most of the
target area.

A front crossing the area on the night of December 14-15 brought variable snowfall to the
area" Strong winds accompanied the front. and sno\\"fall of 3-7" was reported in some areas.
Other areas. such as the Gunnison Valley. received little or no snowfall. Seeding began on the
evening of Dccember 7 (#5). and ended by 1000 MST on the 8th. SNOTEL data indicated up to
0.5" or more of water equivalent in ponions of the targel area.

Seeding was again conducted on the night of December 21.22 (#6), as an upper.level
stonn center passed o\'er Colorado. Winds shifted from westerly to northerly overnight. and
seeding operations were conducted accordingly. Snow water equivalents of about 0.25 - 0.5"
were observed in most of the target area.

A po\\:erful storm system crossing Utah on December 26 brought snow to western
Colorado as well. Seeding began on the e\"ening of the 25th un) in anticipation of this stonn,
and continued until late afternoon on the 26th. Precipitation was not well organized. as the center

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