WMOD00311 ‎(2)‎

• Title: Climatologies and Intercomparisons of Rawinsonde Data Collected During Winter Storm Periods in Utah
• Date: 8/1/1980
• State: UT
• Weather Modification - Doc Type: Report

program, combined with inconclusive. evaluation results, the
State of Utah, Division of Water Resources (DWR) , granted
a contract to NAWC in 1977. to conduct a more detailed and
comprehensi ve design study to guide the future. development
of the Utah snowpack augmentation program. This design study
(Thompson et aI, 1978) considered various aspects of the program
including target areaselecion, ground and aerial sE~eding
techniques, and the specification of seedahility criteria.

2.1 Seedability Criteria

One of the most important aspects of a weather modifi(~ation
program is the specification of seedability criteria. Research
programs over the years have demonstrated that seeding clouds
can produce increases, but can also produce decreases as well,
depending upon atmospheric conditions and seeding techniques.
It is therefore necessary to develop criteria which will allow
seeding during favorable situations and suspension of seeding
during unfavorable situations. Fortunately; several federally
funded research seeding programs have been conducted over
the past 30 years which provide data for ,the establishment
of reasonable seeding criteria.

The major obstacle to direct adoption' of research rE!sul ts
to an operational program from relevant research programs
has been the question of transferability of results from one
geographical location to another. Scientists have recognized
for some time that seeding results vary from one area to another
depending upon such factors as the type and frequency of storms
( cloud climatology) affecting an area and the peculiarities
of a given region in terms of physical topography. Analyses
of various research programs have demonstrated that seeding
response appears to be tied to, among other parameters, the
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