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2.04.8 Climatological Information The permit area is located within the regional box canyon of the Yampa River Valley. Elevations vary from a high. of 8223 feet at the north end oftee permit area to a low of 7100 feet at the ridge bottom along Trout Creek. The rough topography of the mine area causes significant channeling of air masses passing the region. During the evening and early morning hours, air moves toward lower elevations. During the afternoon hours when the sun heats the earth's surface, air tends to flow towards higher elevation. Dp valley flow occurs less frequently in rough terrain than down valley flow 10-20 percent of the year. The remainder of the year, wind direction is variable. Average hourly wind speeds varies with the time of day. .Wind speeds reach maximum values during summer afternoon and are usually associated with up-wally flow. During this time, air is capable of substantial vertical mixing. During the evening and early morning hours, average hourly wind speedo are low. At the mine site, it is estimated that afternoon wind speed will average eight (8) mph and the evening wind speed six (6) mph. Observations also show that the area often has no air movement at all. Wind speeds of less than two mph are expected to occur nearly 20 percent of the time at any time of the day, but moat frequently during early morning or evening. Measurmenta.of annual precipitation at the permit area are unavailable, but historical records from the towns of Hayden and Yampa indlcate that about 16 inches can be expected annually. Precipitation is expected to be greater during the winter months, arriving in the form of snow averaging 160 inches per season. It is estimated that 90 days per year precipitation is greater than the detectable limit of 0.25 mm (0.01 inch). Similar to the entire region; the permit area is subject to large seasonal and daily temperature variations. Monthly records are available for the towns of Yampa, Hayden, and Steamboat Springs. In July temperatures are expected to vary from 81 deg F during the day to 44 deg F at night on the average. January extremes vary from an average of 32 deg F during the day to 1.4 deg F at night. The growing season is expected to be somewhat leas than recorded at Hayden or about 40 to 60 days. The following data was generated from the Pyramid cooperative weather station located only 6 miles SW of the permit area. Additional data covering a period of the last 15 years is presently being entered into the computer, however this permit application has completely quenched the authors environmentally creative bent, and additional weather information for the countless thousands who are anxiously awaiting it will unfortunately be postponed. ~~