2016-02-03_PERMIT FILE - C1981038 ‎(2)‎

• Permit No: C1981038
• IBM Index Class Name: Permit File
• Doc Date: 2/3/2016
• Section_Exhibit Name: Volume 1 2.04 Environmental Resources
• Media Type: D
• Archive: No

52.04 APPLICATION FOR PERMIT FOR SIIRFACE OR IINDERGROUND MINING ACTIVITIES --
MINIMUM REQUIREMENTS FOR INFORMATION ON ENVIRONMENTAL RESOURCES.
• 2.04.8 Climatological Information.
(1) Climatic Characteristics of the North Fork Valley (Cont'd.)
(b) and (c) (Cont'd J
into the lowest portion of the valley or settles above
colder heavier air.
The shape and orientation of the North Fork Valley is
such that the drainage (or katabatic) flow is the domi-
nant flow for most hours of the day. This occurs for
the following reason: the westerly draining orientation
of the valley width in its upper reaches, results in
much of the upper valley bottom being in shadow during
the early and mid-morning hours. The air adjacent to
the south sides of the mountains on the north side of
the river is warmed and rises directly up the side of
the mountains. Since the lower valley is only sparsely
vegetated with generally dry soils, the greatest up-
slope flow occurs in this area. The air from the upper
reaches of the valley thus continues to drain down the
valley until nearly noon (particularly so in winter
when the sun angle is low) and the up-valley (or ana-
• batic) flow does not begin until mid-day. Again, be-
cause of the narrowness of the upper valley, the heat-
ing of the valley flow (say above Somerset and beyond)
is terminated by topographic shading by midafternoon,
and with the air still being warmed and rising in the
lower valley, the North Fork may be one of the best ex-
amples of mountain-valley flow in the Slate of Colora-
do.
Because of the narrowness of the upper valley, the cold
air layer becomes quite deep with the wind velocity at
the mouth of the upper valley usually reaching a maxi-
mum in the early morning hours. Prevailing winds are
from the south southeast with wind speeds of ten miles
per hour occurring in June. Below Paonia the wind
speed appears to decrease sharply as the air spreads
over the lower valley. Because of this strong drainage
wind, frost pockets are not allowed to form, thus
creating a favorable microclimate for fruit tree farm-
ing.
Revised 10/01/87
. 61