WMOD00568

• Project Name: Snowater
• Title: Snow Water Augmentation for the Eastern Slopes of the Rockies - Stage I: Technology Adaptation
• Date: 6/1/1986
• Weather Modification - Doc Type: Report

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There .are atmospheric conditions when cloud seeding can be used to
make these clouds snow in the mountains. This involves the delivery of
ice nucleating agents, either silver iodide smoke or dry ice pellets,
to the regions of supercooled liquid water within clouds. These agents
then greatly increase the concentration of ice crystals which use the
cloud water to grow into precipitation-sized particles that fall as
snow to the surface. Thus, more of the cloud water would be converted
to snow and not lost to evaporation on the leeward side of the
barrier. The increased snowpack would then provide additional
streamflow during spring melt.

Cloud seeding for snowpack augmentation has been undergoing research
and development in the western United States to help alleviate
potential water shortages. Projects are being conducted by various
univer~ities, state and federal agencies including the U.S. Department
of the Interior and the National Oceanic and Atmospheric
Administration (NOAA). These projects are currently being conducted
in California, Colorado, Montana, Nevada and Utah.

Cloud seeding in the mountains has been recently identified by the
United States Secretary of the Interior as "the most cost effective
and promlslng means of meeting the water needs of the Colorado River
basin." (CREST, 1983). Recent results from the U.S. indicate that
cloud seeding may be able to increase the mountain snowpack by about
15 percent (Super and Heimbach, 1983; Cleveland, 1978). In Colorado,
it has been estimated that such increases could augment streamflows by
10 percent, or an additional 2.3 million acre-feet for the Colorado
River basin (CREST,1983). Further details on the present status of
snow augmentation technology and snow augmentation research are given
in Appendixes C and 0 respectively.

2.3 FEASIBILITY FOR ALBERTA: SNOWPACK PROJECT RESULTS

A preliminary assessment of the snow climate and clouds of the
southern Canadian Rockies was recently completed within the Alberta
Research Council's SNOWPACK project. The main objective of this
project was to determine whether a potential exists for modification
of winter snow clouds over the southern Rockies. This project had two
principal components: analysis of the snow climatology of the region
and measurements of the microphysical characteristics of winter clouds
over the mountains.

Analyses of the snow climate provided background information on
snowfalls in the region (Barlow et al, 1983; Thyer et al, 1985).
Different snowfall regimes were found on each side of the continental
divide. The importance of the spring contribution to the total
snowpack was noted. The climate studies indicated that meteorological
conditions within the region were acceptable for the application of
cloud seeding technology.

Measurements of the microphysical characteristics of the winter clouds
over the mountains were made to assess the physical potential for
cloud seeding. A cloud physics research aircraft was used during four

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