150 



SOUTHERN APPALACHIAN REGION. 



the western slope of the Appahicliiaiis in considerabh^ less 

 than on the summits and along the eastern and southern 

 flanks of the mountains, though it generally averages from 

 40 to 50 inches annuaUy on the lower levels. 



As previously stated, the rainfall in the southern Ap- 

 palachian region is occasionallj' torrential in character. 

 The mountain ranges of western North Carolina and 

 northern Georgia are so situated with respect to the rain- 

 bearing winds as to greatly facilitate the rapid condensa- 

 tion of moisture, whether borne by the winds from the 

 Gulf of Mexico or the Atlantic Ocean. The indraft of 

 warm, moist air from these great storehouses of moisture 

 and the subsequent cooling as it is forced up the mountain 

 sides give downpours of rain seldom experienced in the 

 adjacent lowlands. On September 22, 1898, 7.57 inches 

 of rain fell within 24 hours at Linville, 6 inches at Lenoir, 

 8.30 inches at Paterson, 6.75 inches at Marion, and 5.75 

 inches at Flat Rock. During August, 1901, the total 

 rainfall for the month at Flat Rock was 30 inches; at 

 Highlands, 30 inches; at Henderson ville, 26 inches; at 

 Horse Cove, 26 inches; at Paterson, 24 inches, and at 

 Marion, 21 inches. The precipitation for the year 1898 

 in western North Carolina at Highlands was 105.25 inches; 

 at Horse Cove, 99.97 inches; Flat Rock, 78.39 inches, and 

 Linville, 71.05 inches. These heavy downpours naturally 

 cause destructive floods in the streams whose headwaters 

 penetrate the mountain region. The severity of the floods 

 is in a large measure mitigated by the fact that a large 

 proportion of the rainfall is conserved by the forest cover- 

 ing, which abounds on the greater part of the area, and is 

 thus prevented from reaching the streams quickly and in 

 great volume, as would be the case were the mountain 

 sides and the summits bare. It is a mistake to suppose 

 the forests per se tend to increase precipitation. The 

 precipitation would be equall}^ heavy, forest or no forest. 

 In the latter case it would run off more quickly and the 

 regimen of the streams would be much more irregular 

 than in the case of a forested area. 



Not much can be said of the relative humiditj^ of the 

 higher elevations, since no observations have been made. 

 Along the western edge of the Piedmont Plateau the air 

 is considei'ably drier than on the coastal plain. Tables of 

 monthly mean relative humidity for Atlanta, Ga., Char- 

 lotte and Asheville, N. C, and Chattanooga and Knoxville, 



