Laserfiche WebLink
By comparison of locations and elevations it appears that 0.5°F • <br />change in mean annual temperature could be expected for each <br />100-foot change in elevation. The highest area in the Seneca II <br />lease is 8105 feet and was calculated to have a mean annual <br />temperature of 36.7°F mean annual temperature (MAT) and the lowest <br />elevation of 6556 to have a MAT of 45.0°F. Highs of 95°F and lows <br />of -40°F may occur. <br />Similarly, rainfall was estimated to vary by about 0.25" per 100 <br />feet in this locale. Elsewhere, 19" at 7500 feet had been used as <br />a general base which gave a value of 16.6 for the lowest elevation <br />and 20.5" for the highest elevation in the area. Similarly, the <br />frost-free days computed to 93 days for the lowest elevation and 67 <br />days for the highest elevation. Table la shows the general relation <br />of elevation to climatic factors as calculated for Seneca II mine <br />areas. <br />It is recognized that these are estimated based on very limited • <br />data but they do serve to point up the fairly wide range of climate <br />over these hills and valleys and are used in the map unit descriptions <br />to illustrate ranges in local climates for these units. <br />The following is taken from the Seneca 2W Environmental Impact Report <br />of January 1975. <br />"While elevations such as those at the mine area often have snow duzing <br />October, November and December, most of the October and November <br />moisture is in the form of rain and most of the early snowfall melts <br />in the warmer weather between storms. Generally, snow does not begin <br />to accumulate to form the winter snowpack until the latter half of <br />December. <br />The snowpack in the mine area is expected to develop during the winter <br />months until late March or early April. By the end of the winter <br />season, there should be between one and three feet of snow at the <br />8,000 feet contour. This snowpack should contain between two and six <br />inches of moisture. Only a small fraction of the snowpack is ex- <br />pected to be converted to stream runoff by the warmer temperatures <br />of April and May. However, since, at the relatively lower elevations <br />in Craig, Colorado, there is continuous snow cover for 60 days or <br />more during most winters, the snow cover will last even longer at <br />the higher elevation of the Seneca 2-W lease area. <br />-4- <br />