BOARD00272

• Board Meeting Date: 7/28/2003
• Description: Flood Section - Weather Modification Program
• Board Meetings - Doc Type: Memo

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CWCB Wintertime Weather Modification Report

Fa112002 - Spring 2003 .

Executive Summary
Background: The state has had a weather modification-pelTI1itting program since 1972 and
activity and funding for programs has varied over the years. Vail, Colorado has the longest continuous
program at 23 years. CWCB staff member Joe Busto was delegated the responsibilities for this program
in July 2002 by Director Rod Kuharich.
Vail Report: A report by Larry HjelTI1stad of Western Weather Consultants dated April 2001
quantified results from ten years of seeding at Vail by SNOTEL and ski resort physical measurements.
The CWCB b'elieves this report and the toll of the drought influenced water managers and led to the
expansion of programs and new programs within the state.
New permits: In 2001-02 there were four pelTI1its in Colorado for the Grand Mesa, Vail, Western
San Juan Mountains and around Telluride. In 2002 three new pelTI1its were requested for wintertime
seeding operations and one five year renewal of a permit and they were: (1) the Central Rockies Program
covering parts of the Colorado, South Platte, and Arkansas watersheds (2) the Eastern San Juan
Mountains and expansion of the Western San Juan Mountain Program (3) Telluride renewed its five year
permit and (4) Gunnison County.
Recent Trends: Recent expansion of weather modification programs indicates a response to the
drought of 1999-2002 and growing concern with meeting present and future water demands. It is
anticipated that programs will continue and expand in the future as a tool to help attempt to meet those
needs, A series of wet years could potentially lessen enthusiasm and funding but programs may continue
ifproven as a resource tool that augments snowpack and streamflow.
Public concern: Public meetings to address conderns about cloud seeding in 2002 could be .
categorized into four main concerns or questions, Is this taking water from one area and depriving it from
another? Are there negative effects of silver iodide on the environment? Should we be messing with
nature? Does it really work?
Avalanche suspension criteria: The state's pelTI1itting program is designed to ensure qualified
program operators and to monitor the programs through suspension criteria placed on snow water
equivalents at SNOTEL sites in the target area and operato~ suspension during avalanche center warnings,
Graphing and tracking Snow Water Equivalent and reporting to the state was a requirement of 2002-2003
permits for project sponsors as well as the meteorological qonsultants as an attempt to get project
sponsors involved in the policing and evaluation of the programs, the CWCB monitors this also. A
problem identified during the year with avalanche center forecasting was the forecasting relationship to
the permit. In February 2002 there were close to 150 avallUlches in one week and program operators were
unclear if general warnings applied to their target area mountain ranges. Operations ceased for a few days
during this heavy avalanche dlUlger period but it needed tOibe clearer both to the CWCB staff and
consultants exactly when to suspend operations, The CW<DB met with CGS AvallUlche Center's Knox
Williams in summer 2003 discuss funding more specific forecasting in target areas and email the
Avalanche Center warnings directly to the CWCB and cloud seeding operators. A scope of work is being
developed by the CGS and will similar to the CDOT arrangement for avalanche forecasting and warnings
as it relates more to highways. This type of more specific forecasting for cloud seeding was done
previously in the 1980s,
Weather Modification Association Journal: The CWCB purchased all five volumes ofthe
Weather Modification Association J oumal at the annual conference. This collection includes
approximately 500 abstracts and research/operational pap'ers on the topic of weather modification that .
range from 1971 - 2003, These technical papers are a gQod resource on the topic. These papers are not
currently available on the web and the CWCB might explore purchasing the rights to the papers and

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