WMOD00259

• Applicant: Western Kansas Groundwater Management
• Project Name: Western Kansas Weather Modification Program
• Date: 1/1/1999
• Weather Modification - Doc Type: Report

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IV. OPERATIONAL SUMMARY - 1998

Table 1, on the following page, summarizes the relevant 1999 WKWMP operational flight
and seeding information plus it presents all the days upon which crop-hail insurance claims were
reported. Each flight was broken down into whether it was:

R... to increase Rain only
H...to reduce Hail only
C...a Combined flight, both to increase rain and reduce hail, or
O...an Observation flight---cloud examination only, no seeding was performed

Other operational information is found in the Appendices, in the back of this report:

Appendix A - Historic Project Operational Activity Summary
(seeding and observation flights)
Appendix B - Historic Monthly Number of seeding Days for Hail and/or Rain
Augmentation
Appendix C - Historic County Weather Modification Participation
Appendix D - NOAA Form 17- 4A, Final Report on 1999 monthly seeding activities

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In 1996, we stated the storm season that year was an extreme, off-the-scale kind of year
that may occur only once in a generation. When compared to similar data from earlier and later
years, no operational records have been broken since 1996 (see Appendix B, page 73), however,
there were eight seeding days this September equaling the most for any September going back to
1987 for the four years that the WKWMP ran longer than it did this season. In 1987 the program
ran through Sept. 30th. Although more "normal" season~ have since appeared, we are still on the
high side of the curve for the average number of operational days and hail-days in a season. In
1999 there were 68 seeding days, the same as in 1998, but 74 days in 1997.

Most statistics fell below last year's levels despite the same number of seeding days. When
we look at total seeding time, 1999 fell to 36,290 minutes (605 hours) from 77,939 minutes (1299
hours) in 1998, a 53% decrease. Silver iodide consumption dropped from 167,752 grams in 1998
to 13 5,443 this year, a nearly 19% decrease over 1998. Respective year -over -year seeding flights
in 1999 vs. 1998 were as follows: hail (only) there were 362 vs 290; for rain augmentation (only)
flights numbered 31 to 87, whereas, the combined flights seeding for both hail and rain were 80
vs. 221. Together, all seeding flights add up to 473 flights in 1999 vs 598 in 1998---125 fewer
flights this season over 1998. Although there were almost 70 more flights in 1999 in the
'Observation" and' Other' categories, the total flight time for both years was nearly identical.

The semi-surprise this year was that the cloud-top (Cheyenne aircraft) seeding time and
the amount of dry ice dispensed were nearly identical to 1998. This season there were 3165
kilograms CO2 dropped vs. 3159 kilograms in 1998; seeding time was 83,804 seconds (23.3

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