Climatology of the Georgia Mountains

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CLIMATOLOGY OF THE GEORGIA MOUNTAINS

Georgia Mountains: An Introduction Located in the northern quarter of the state, the Georgia mountains and includes the Blue Ridge, Ridge and Valley, and Appalachian Plateau physiographic provinces. Within these provinces are the following geologic divisions: Chickamauga Valley, Armuchee Ridge, Lookout Mountain, The Great Valley, Cohutta Mountains, McCaysville Basin, and the Blue Ridge Mountains. The region is characterized by forest-covered mountains and narrow valleys dominated by farms and pastures. Elevation varies considerably from less than 1,000 ft. up to 4,784 ft.; Brasstown Bald, Georgias highest point, is located in this region. Major river systems located within the region include the Conasauga, Cossa, Tennessee, Chattooga, Hiawassee, and Chattahoochee Rivers. Ecologically, the Georgia mountains are quite diverse. Along with surrounding moun- tainous lands, this area harbors more salamander species than anywhere in the world.

Blairsville (1,916.5 ft.) 9 100 8 90 7 80 6 70 60 Georgia Mountains: Precipitation Profile 5 50 In the Georgia mountains, precipitation is relatively consistent month to 4 40 month, yet it does vary by location. Precipitation (rain and snow) tends to 3 30 2 20 be greatest in the northeast corner of the region and drops off to the 1 10 southwest. For example, Blue Ridge averages 5 inches more annually than 0 0 LaFayette; most of this difference arrives in the spring and summer months. Blue Ridge (1,839.4 ft.) 9 100 Region-wide, the driest months tend to be in the fall (September, October,

8 90 F) and November). During this season, precipitation averages between 9 and ° 7 80 15 inches. The historical record suggests that areas in the Georgia Moun- 6 70 60 tains can experience month-long dry spells. For example, October 1938 5 50 and October 1963 were extremely dry months in which less than 0.01 4 40 3 30 inches of rain was reported. In contrast to the dry season, a cool season Precipitation (in.) Precipitation 2 20 ( Temperatures rainfall maximum predominates in the Georgia Mountains, with January or 1 10 March being the wettest month of the year. This is caused by cyclonic 0 0 storms moving across the country on a regular basis during the winter and Calhoun (654.7 ft.) 9 100 early spring. Mountain elevations uplift moist air, resulting in considerable 8 90 precipitation in the region. Extreme rainfall events are not uncommon. For 7 80 6 70 example, on September 9, 1975, Dalton received in excess of 10 inches of 5 60 rainfall in a 24 hour period. Similarly, just 10 years later, Blue Ridge was 4 50 40 hit with 8.27 inches of rainfall in a 24 hour period, causing numerous land- 3 30 slides in the area. This region receives the most snowfall in the state. For 2 20 example, the Blizzard of 1993 blanketed north Georgia with up to 2 feet of 1 10 0 0 snow. OCT JUL SEP NOV DEC FEB APR JUN JAN MAY AUG MAR

Georgia State Climate Office http://www.bae.uga.edu/climate/ Driftmier Engineering Center [email protected] University of Georgia Spring, 1998 706-542-8806(fax) Athens, Georgia 30602-4435 98-02a 706-542-6067 CLIMATOLOGY OF THE GEORGIA MOUNTAINS

Georgia Mountains: A Temperature Profile Going to EXTREMES! Temperatures in Georgias Mountains are quite variable, due in Annual Hi Temp Lo Temp Prcp Station Date ° Date ° Date Date large part, to the regions topographic relief (i.e., elevation dif- Snow (in.) ( F) ( F) (in.) ° ° ferences). Region-wide annual temperatures average in the B"lairsville 138.010991066/29/36-11"/28/4052.53/11/5 ° ° high 50s, with summer temperatures in the low 80s. Of course, B"lueRidge161.01899960/22/64-11"/9/7084.2710/4/6 because of the gradual drop in elevation from the northeast to ° ° C"artersville98.518961089/27/54-1"/21/8560.03/18/9 the southwest, temperatures can vary considerably. Continu- ° ° ° ous days with temperatures exceeding 90 F are not uncom- C"layton202.012961071/12/30-11"/21/8584.0210/4/6 ° ° mon, though this also varies from northeast to southwest. For D"ahlonega105.513941072/29/52-11"/21/8567.283/30/7 ° ° example, Clayton experiences° 15 days per year with tempera- D"alton138.013991060/27/88-11"/21/85150.49/24/7 ° ° tures exceeding the 90 F mark, whereas that value increases L"aFayette231.016991073/28/52-11"/20/8560.992/16/9 to 53 days at Rome. Low temperatures do not follow the longi- ° ° R"ome134.017991069/28/31-1"/21/8567.6710/26/9 tudinal trend as described for high temperatures; Clayton and ° ° T"occoa105.016971075/12/30-1"/30/6684.68/16/8 Rome both experience between° 70 and 90 days per year in which the mercury drops below 32 F. Elevation greatly influences the number of days of exceptionally cold conditions.

Clayton (1,879.0 ft.) 9 100 8 90 7 80 70 Georgia Mountains: Climatic Elements 6 The climate of the Georgia Mountains is influenced by both geographic and 5 60 50 4 meteorologic elements. Temperature and precipitation change daily (di- 40 urnally) because of topographic position. Elevation is also an important 3 30 2 20 factor influencing the climate of the mountains because as elevation in- 1 10 creases, air temperatures cool. Additionally, as air rises, its ability to 0 0 hold water reduces, thus a tendency for higher precipitation at higher Helen (1,439.6 ft.) 9 100 elevation. Another important factor includes the great distance to the 8 90 F) Atlantic Ocean and Gulf of Mexico. These bodies of water tend to minimize 7 80 ° 70 diurnal fluctuations in temperature because of the time it takes for water 6 60 to heat and cool. Winter climate can be influenced by blasts of arctic air 5 50 4 40 moving southward out of Canada. Spring and summer convective storms, 3 30 associated with fronts moving through the region, bring great amounts of Precipitation (in.) Precipitation 2 20 ( Temperature precipitation, especially if such fronts stall in the mountains. 1 10 0 0 LaFayette (800.6 ft.) 9 100 8 90 7 80 6 70 5 60 4 50 40 3 30 2 20 1 10 0 0 OCT JUL SEP NOV DEC FEB APR JUN JAN MAY AUG MAR