WMOD00206

• Applicant: North American Weather Consultants
• Project Name: Grand Mesa
• Date: 11/1/1985
• Weather Modification - Doc Type: Contract

from shallow, stable orographic situations to deep storms with strong
embedded convective cells. The experiments will be limited in areal
extent and duration. Their purpose will not be to change the seasonal
snowfall in the area, but to determine the effectiveness of particular
seening agents ann rates of release during given cloud conditions. The
intended target for these efforts is within a band extending approxima-
tely 5 miles either side of Colorado Highway 65 where it crosses the top
of Grand Mesa. Resulting data will be used to optimize the design of
future larger-scale seeding programs intended to increase the seasonal
snowpack over a significant area. Efforts during the remaining contract
years are anticipated to be similar in scope. The period of operations
for FY85 will be between January 2 and March 31, and from November 1
through March 31 for the remainder of the contract years.

80th ground-based and airborne seeding will be utilized in the experi-
ments. All dispensing equipment, nucleating agents, supplies, and parts
necessary to operate and maintain the units and the aircraft will be
furnished by the Government.

Ground generators to be used, will utilize a 3 percent by weight solu-
tion of AgI in acetone comp1exed with NH41. .The seeding rate will be
about 30 g AgI/hr for each generator used. It is anticipated that the
maximum number of generators which would be operated simultaneously
would be three, although the majority of the experiments will likely use
only one of two generators. The effectiveness of the generators to be
used ranges from approxiamte1y 10 exp 14 to 10 exp 15 ice crystals per
gram of AgI at -10 oC, depending on windspeed across the burner head.
Ground generators will be portable, and will be transferred from site to
site as knowledge of the transport and diffusion characteristics is
developed. Nine sites have been selected for potential utilization
during the 1984-85 winter season. These are located as follows:

Site No. Location
1 T.llS., R.96W. , Sec. 14, SEl/4SEl/4SEl/4NEl/4
2 T .12S., R.96W., Sec. 22, NWl/4SEl/4SEl/4NWl/4
3 T.12S., R.97W. , Sec. 9, NEl/4SEl/4NEl/4SEl/4
4 T.12S. , R.97W., Sec. 3, NWl/4NWl/4SWl/4SEl/4
5 T.12S., R. 97101., Sec. 13, NWl/4SEl/4SWl/4SEl/4
6 T.12S. , R.96W. , Sec. 29, NWl/4SWl/4NWl/4SEl/4
7 T .13S., R.97W. , Sec. 14, SWl/4SWl/4NEl/4NEl/4
8 T.12S. , R.97W. , Sec. 24, SWl/4SWl/4SWl/4NEl/4
9 T.13S. , R. 96W~, Sec. 6, SEl/4SWl/4SWl/4NWl/4
Other si tes may be requ ired for use duri ng later contract years.

Airborne seeding during the 1984-85 winter will be conducted using dry
ice pellets. These will be dispensed at rates ranging from 0.1 to 1 kg
per kilometer of flight. Releases may be made in cloud, or from above
cloud top. Pellet size will be approximately 1 to 2 cm in diameter.
Effectiveness values of approximately 10 exp 11 to 10 exp 12 ice
crystals per gram are assumed. Pellets will be dropped along a line

C-4