PERMFILE116446

• Permit No: C1980001
• IBM Index Class Name: Permit File
• Doc Date: 12/11/2001
• Section_Exhibit Name: 2.6 CLIMATOLOGY & AIR QUALITY
• Media Type: D
• Archive: No

Doc Date:12/1112001 III I II I II I II IIII III
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5/~ i 2.6 CLIMATOLOGY AND AIR QUALITY
• 2.6.1 REGIONAL CHARACTERISTICS
The Edna Mine is located in an area of open high mountains (National Atlas,
1969) whose climote is typical of semi-arid steppe regions (BLM, 1977). Because of
the diverse topography, the climate of the Edna Mine is more dependent upon local
features Than regional or global trends.
2.6.2 PRECIPITATION
The Edna Mine is approximately midway between the national weather service
stations at Yampa and Steamboat Springs. The Steamboat Springs Station is located
at 40° 30' latitude, 1060 50' longitude and at an elevation of 6,770 feel. The Yampa
Station is located at 400 09' latitude, 1060 54' longitude and at an elevation of 7,892
feet. The mean annual precipitation at Yampa is 16 inches. It's monthly distribution,
as well as maximum and minimum extremes are shown in Exhibit 2.6-I. In Steamboat
Springs, the mean annual precipitation is 24 inches. It's monthly distribution and
extremes are shown in Exhibit 2.6-2. The wide difference between the two stations
is caused by topographic effects that respectively reduce and increase pre-
cipitation; Yampa is in the rain shadow of the flattop mountains while Steamboat
Springs has high peaks immediately to it's east which orographically stimulate
precipitation. Thus, for storms coming from the west, which is typical of the winter
snowstorms, Yampa receives less precipitation than Steomboat Springs as is shown in
the monthly figures. For the Edna Mine, which has neither the orographic generation
of precipitation by mountains to it's east or a shadow effect from mountoins to the
west, monthly precipitation should lie between The values for Steamboat Springs and
Yampa. Winter precipitation comes from regional snowstorms of fairly long duration,
while summer precipitation occurs as short duration but very intense localized
thunderstorms. This is reflected in The greatest daily precipitation values, which are
highest in September and October. For both Steamboat Springs and Yampa, June, July
and August ore The only snowfree months, with the heaviest snowfall occurring
between December and March. The total annual snowfall is 165 inches for Steamboat
Springs and 120 inches for Yampa. Snowpack is nearly continuous from late October
through the middle of April, with the snowmelt nearly completed by May.
LJ
Revised 7-81 2,6_I