WMOD00268

• Applicant: CWCB
• Sponsor Name: USBR
• Project Name: Final Report Weather Damage Mitigation Program
• Title: Numerical Simulations of Snowpack Augmentation for Drought Mitigation Studies in the Colorado Rocky Mountains
• Prepared For: USBR - WDMP
• Prepared By: Curt Hartzell, Dr. William Cotton, Joe Busto
• Date: 9/1/2005
• State: CO
• Weather Modification - Doc Type: Scientific Study

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In the 2003 National Academy of Sciences (NAS) report enlitled Critical
Issues in Weather Modification Research, the Committee concluded for weather
modification in general, "there still is no convincing scientific proof of the efficacy
of intentional weather modification efforts... This does not challenge the scientific
basis of weather modification concepts. Rather it is the absence of adequate
understanding of critical atmospheric processes that, in turn, lead to a failure in
producing predictable, detectable, and verifiable results.- However, in a more
positive conclusion the Committee noted, "There are strong suggestions of
positive seeding effects in winter orographic glaciogenic systems. ~

The NAS report (2003) recommends a coordinated research effort and
lists a few especially promising possibilities where substantial further progress
may occur, including, "Orographic cloud seeding to enhance precipitation. Such
a program could build on existing operational activities in the mountainous
western United States. A randomized program that includes strong modeling
and observational components, employing advanced computational and
observational tools, could substantially enhance our understanding of seeding
effects and winter orographic precipitation'- Such a research program is needed,
but as Professor Roland List noted (2005), it should be understood that the only
reliable statements made in randomized experiments are statistical in nature.
Statistics do not give "scientific prooF of anything, it only gives a measure of the
outcome, such as the confidence level.

Within the United States, there are over 65 operational weather
modification programs in 10 western states; no federal funding currently is
supporting any of these operational activities. The NAS report (2003) states,
"Despite the large number of operational activities, less than a handful of weather
modification research programs are being conducted worldwide. After reaching a
peak of $20 million per year in the late 1 970s, support for weather modification
research in the United States has dropped to less than $500,000 per year.-
Currently scientists have the knowledge and tools to advance the field of winter
orographic cloud seeding for the benefit of water users, but not the research
funding to fully verify the technology. In order to identify the optimum conditions
and methodologies for winter orographic cloud seeding operations, all such
programs in Colorado (and elsewhere) should include a well-defined research
component to the extent funding will allow.

1.4 Colorado Weather Modification Permit Program

The state of Colorado has had a weather modification-permitting program
since 1972. Authority for this program resides in the Executive Director's Office
of the Colorado Department of Natural Resources. Since 1987, this authority has
been delegated to the Director of the CWCS. The CWCS's Flood Protection
Section has been administering Colorado's program lor issuing permits for cloud
seeding activities since 2001. For the 2003.2004 winter season, there were nine
active permits for ground. based wintertime precipitation enhancement programs.