WMOD00314

• Project Name: Uintah Ecology Project
• Title: Potential Ecological Impacts of Snowpack Augmentation in the Uintah Mountains, Utah
• Date: 4/20/1981
• State: UT
• Weather Modification - Doc Type: Report

I
I
I'
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I

25

SPATIAL AND TEMPORAL DISTRIBUTION
OF PRECIPITATION
It has seemed useful to us to determine how precipitation varies in
time and space in the study area. We consider first how precipitation
varies in space in the Uinta Mountains. It has long been accepted that
the major part of the winter storms that strike northern Utah come from
a northwesterly direction as moist air masses from the north Pacific
Ocean are driven inlands by the prevailing westerly winds (Eubank 1979).
Since the long axis of the Uintas is oriented east and west, we wondered
whether the northwestern 'portion of the range received more precipita-
tion than the south slope which should experience a "rainshadow" effect,
if the postulated weather patterns noted above did indeed prevail. By
the same logic, one might expect the eastern end of the range to receive
less precipitation than the western end.
In order to evaluate the foregoing hypotheses, we grouped SCS
precipitation storage gages by their location on the range (i.e., north
or south slope; east or west end of the range). The breakdown of sta-
tions is shown in Table 2-2. The north-south breakdown was made along
the watershed divide running east and west with the Provo and Weber
drainages being tallied as part of the north slope. The east-west break
was made along a line running north and south at longitude 110024' 30".
This line ran just to the west of the Henry's Fork Station and just to
the east of the Lakefork Mountain Station (Figure 2-2).
In order to generalize the results of our analyses, separate linear
regression analyses relating elevation to precipitation were made for
all north slope, south slope, west end and east end stations. The
results are shown graphically in Figure 2-3. Sample size for each