WSPC07673

• File Number: 8200.700
• Description: Colorado River Basin General Publications - Augmentation-Weather Modification
• State: CO
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 2/27/1978
• Title: Colorado Emergency Weather Modification Program - 1977-1978 Water Year
• Water Supply Pro - Doc Type: Report/Study

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003348

What are the Results of the Program?

A technical assessment of the program- is in progress. It will be

several months before the required upper air, precipitation and streamflow

data will be available for the completion of the assessment of this
winter's program. While this assessment should provide guidelines on the

effectiveness of this cloud seeding application effort, it will probably

take a number of seasons to increasingly delineate the actual effectiveness

of such operational programs as distinct from assuming that the results are

the same as those suggested by research programs. The program this winter

assumes that the results will be comparable to those indicated by previous

research programs in the state. These research programs indicated a

10-20% overall increase in snowpack but with the increases coming only

on a portion of the days that meet specific seedability criteria. Only

these periods satisfying the criteria are being seeded in the present

program. The previous research indicated that other periods are not

suitable for cloud seeding to produce precipitation. If the effects of

the seeding this winter are comparable to those originally indicated by

the research experiments, the increases in snowpack from this winter's

program could be substantial. There has been a high frequency of eastward

moving weather systems that have brought upper level (mountain top level)

Pacific moisture into the state, and the meteorological conditions during

many of the episodes have met previously defined favorable seedability

criteria. Cloud seeding, consequently, should have been effective more

frequently than is the case in a normal winter.

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