Southern Blue Ridge Province: Geographic Location & Influences
The Appalachians — Created between 300 and 250 million years ago as a result of periods of mountain building brought about when the North American continental plate collided with the plates forming the European and African continents — extend some 2,000 miles from Canada’s Gaspe Peninsula to north Georgia and Alabama. they have been described as “The most elegant mountain range in the world.”
The Southern Appalachians can be defined as the ranges south of the point in northeastern Pennsylvania to which glacial ice sheets extended at the height of the Wisconsin epoch 18,000 years ago. THat region consists of four geographic provinces: Piedmont, Blue Ridge, Ridge and Valley, and Plateau. The Blue RIdge is by far the most significant in regard to mountainous terrain.
The Blue Ridge Province of the Southern Appalachians extends from just south of Harrisburg PA to the hills of north Georgia just north of Atlanta, encompassing mountainous portions of southwestern Virginia, western North Carolina, east Tennessee, northwest South Carolina, and north Georgia. The Blue Ridge can be divided into northern and southern provinces, with the Southern Blue RIdge Province (SBRP) consisting of the terrain south of Mt. Rogers in southwestern Virginia to Mt. Oglethorpe in north Georgia.
The eastern front or escarpment of th SBRP is clearly defined from Virginia into South Carolina. On its western front the SBRP consists of the Unaka, Great Smoky, Unocoi, and other massive ranges. Connecting the eastern and western fronts are transverse ranges: Blacks, Great Craggies, Great Balsams, Nantahalas, and many others. THe Appalachian system as a whole reaches its greatest elevation, largest mass, and most rugged topography in the SBRP where 125 peaks rise 5,000 feet or more, with 49 of them surpassing 6,000 feet. (From Mt. Rogers in Virginia northward to the Gaspe Peninsula only Mt. Washington in New Hampshire exceed 6,000 feet.)
This topography profoundly influences the region’s average temperature (and thereby its plant and animal life, which exhibit strong northern affinities). The principle of verticality states that for each 1,000 feet gained in elevation the mean temperature decreases about 4-degrees F, equivalent to a change of 250 miles in latitude. (This means that if you travel from the lowest elevations in the SBRP at about 1,000 feet to the higher elevation above 6,000 feet, it’s the equivalent of traveling more than 1,200 miles northward in regard to the habitats you will encounter.)
The SBRP is situated where winds bringing saturated air masses from the Gulf of Mexico and the southern Coastal Plain are cooled and lose much of their content. (Air cools while rising to pass over a mountain range and can hold less moisture than warm air; therefore, heavy condensation occurs when large fronts first encounter massive ranges, as is the instance along the Blue Ridge divide.) The heaviest rainfall in the entire Appalachian region occurs along the GA-NC-SC borders, resulting in annual rainfalls of over 90 inches in many area. (As much as 145 inches have been recorded with regularity since 1935 along the GA-NC line by the Coweeta Hydrologic Lab located near Otto, NC). Taking this into consideration, some professional observers now refer to the area as a temperate rain forest. The higher elevations of the SBRP can be thought of as a peninsula of northern terrain extending into the southeastern US where typical flora and fauna of northeastern and southeastern North America flourish. The region features approximately 1,500 vascular plants (man of which are considered to be showy wildflowers) and 125 species of trees (in all of Europe there are only about 75 species).
–George Ellison, Bryson City, NC