CWCB Wintertime Weather Mod Report

• Project Type: General OWC
• Applicant: Weather Modificaton
• Project Name: Colorado Weather Modification Program
• Title: CWCB Wintertime Weather Modification Report Fall 2002 - Spring 2003
• Date: 7/1/2003
• Water Conservation - Doc Type: Final Report

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2.0 FEASIBILITYIDESIGN STUDY

The first task required in the contract between NA WC and the County was the
preparation of a feasibility/design study for the Gunnison County cloud seeding program.
This study was completed by NA WC (Griffith and Yorty, 2002) and provided to the,
County on December 17,2002, Since this study provides the basis for the pro!!:ram
that was conducted durin!!: the 2002-2003 winter season. the findin!!:s of this study
are provided in the folIowin!!: sections.

2,1 Climatological Precipitation Information

The Natural Resources Conservation Service (formerly the Soil Conservation
Service) has historically been responsible for the collection and publication of
precipitation information throughout the mountainous areas of the western United States.
Early observations during the winter time have included montWy manual measurements
of snow water content and depth at selected locations commonly referred to as snow
surveys. In more recent years (beginning in the 1980's), an automated system known as
SNOTEL has been implemented. This system provides multiple readings of snow water
content and precipitation on a daily basis. NA WC reviewed the available data for
Gunnison County. Table 2-1 provides the average montWy precipitation amounts
(October through April) for four upper elevation sites in Gunnison County. Table 2-2
provides the average cumulative snowpack water content for the same sites for the
October through April period. The six-month period of November through April appears
worthy of further analysis regarding winter cloud seeding potential over the higher
mountains in the County. October is a transition month with limited snowpack'
accumulation in the mountains of Colorado, plus relatively warm temperatures which
tend to limit the cloud seeding potential as will be discussed in a later section.