WMOD00295

• Title: Guidelines for Cloud Seeding to Augment Precipitation
• Date: 1/1/1995
• Weather Modification - Doc Type: Report

22

CLOUD SEEDING

are associated with 2-8% increases in total season visits (skier visits equal
the number of lift tickets sold). His "conservative" estimates of retail
expenditures by these additional skiers were in the $0.5-$10 million range
for six ski areas during the early 1980s. The activity in the Colorado ski
industry has magnified manyfold since then, so early-season snow is all
the more important to state economics. The antithesis is that "additional
snow in the midseason probably does not significantly increase skier
visits and attendant retail expenditures" (Sherretz 1984). The Colorado
counties that do not host ski areas benefit from wages paid to residents
who commute to jobs at ski areas.
Snowmaking machines at the lower elevations of the ski slopes have
greatly increased the stability of opening day and low-snow periods.
However, some ski areas do employ cloud seeders, especially to try to
insure reliable snow cover at the highest elevations. The relative value of
the benefits might be estimated by determining the cost of meeting the
requirements by these alternative methods.
A frequently expressed concern of residents in cloud seeding project
areas is that more snow will mean greater snow removal costs. From a
local viewpoint, it has been suggested that citizens whose lifestyles and
incomes are negatively impacted by enhanced precipitation may require
compensation, which would be computed on variables such as wages
lost or costs incurred from incrementally more adverse weather (Weis-
becker 1974). However, it has been found to be very difficult to assess the
cost of removing an additional increment of snow.
Responding to such concerns, the Colorado Department of Natural
Resources assessed county snow removal procedures and developed a
computer model to simulate snow removal costs (Sherretz and Loehr
1983). Costs were simulated because most counties do not keep detailed
records of snow removal expenses. Information on wages, equipment,
and removal procedures was obtained by interviewing road maintenance
foremen. Variations in these factors and snow-removal strategies are
reflected in the time required to remove a certain amount of snow in
different counties (Figure 2.3). A large (25%) increase in snowfall due to
cloud seeding was assumed in one-third of the observed storms. Esti-
mated costs per employee for removing snow from unseeded storms
ranged from $1300 to $11,000 in a winter of heavy snowfall. Additional
snow from seeding was estimated to increase removal costs by 0.8-12.6%
in a heavy snowfall winter. The average cost increase over all counties
studied was 6.1% in winters with heavy and average snowfall and 4.9%
in winters with low snowfall. Somewhat in contrast, the California De-
partment of Transportation (unpublished) found that the increases in
snowfall in near average or below average precipitation years are within
the range covered by the major fixed costs for equipment and labor. In
California, spring flooding can be a problem, so cloud seeding operations
might be suspended in years when snow depths significantly exceed
average. Colorado mountain and Western Slope counties were encour-
aged to develop procedures for collecting data of sufficient detail to