WMOD00054

• Applicant: Western Weather Consultants
• Project Name: Vail Pass
• Date: 11/1/1984
• Weather Modification - Doc Type: Report

,

FINAL OPERATIONAL SEEDING SUMMARY REPORT
FOR THE
CENTRAL COLORADO MOUNTAINS
\-1EATHER ~IODIFICATlON PROGRAM

WESTERN WEATHER CONSULTANTS, INC. submitted an application for a permit
to augment natural winter precipitation in the Central Colorado mountains, to
the Colorado Department of Natural Resources, on August 18, 1984. The seeding
areas requested for the operational 1984-1985 Winter Snowpack Augmentation
Program were the drainages around the Vail and Beaver Creek ski areas.
This application was discussed at a public meeting held on October 19, 1984,
before David H. Getches, Executive Director and Barbara Welles, Weather
;.1odj.fication Program Director, Colorado Department of Natural Resources,
in Vail, Colorado. WESTERN WEATHER CONSULTANTS, INC. was represented by
Lawrence M. Hjermstad, President.

WESTERN WEATHER CONSULTANTS, INC. received a Weather Modification Permit
for the drainages around the ski areas granted effective November 9, 1984, and
in force until March 31, 1985. One of the stipulations of the permit was that
no generator should be operated under conditions when the plume might be
expected to reach Leadville, Colorado; other stipulations related to seeded
area boundaries, generator sites, the selection of weather systems suitable
for seeding and program suspension criteria.

The program was operationally ready by November 1, 1984, with eight
ground-based cloud nuclei generators in place to seed the Vail and Beaver
Creek ski areas. AIl of the generators were manually operated and utilized
silver iodide as the nucleating agent.

The first seeding for the 1984-85 winter season was initiated on November 14;
this was fol1owed by three more seeding events during November. During
December there were six seeding events. At the end of December. 1984, the snow-
pack readon.Vail mountain was estimated to be about 112% of normal from snotel
measurements. Two other snowpacks around the immediate area were measured at
106% and 117% of normal.

During January, 1985, there were six more seeding operations over portions
of 10 calendar days. Snow amounts during these storm events were light to
normal. At the end of January, 1985, snowpack readings on Vail Mountain
were measured from the snotel to be at 101% of normal while four other snowpacks
in the immediate area ranged from 93% to 98% of normal with only one site
above normal at 115%.

During February, 1985, frequent light snowfal1s continued with four storm
.... events being seeded. Snowpacks in the vicinity of the seeding program continued
"to hold their moisture content at slightly below to near normal ranging from
84% to 103%. The snowpack at Vail Hountain was measured at 105% of normal.