As the end of winter approaches in the Southern Hemisphere, snow paints the Andes. The Andes—the longest series of mountain ranges in the world—span about 7,242 kilometers (4,500 miles) and run through seven countries. The segment shows about 1,200 kilometers (750 miles) of the range in Chile and Argentina. The snowpack that accumulates in the mountains each winter is the primary source of water for communities at lower altitudes. According to a report by the Intergovernmental Panel on Climate Change, however, frozen areas in the Andes are generally retreating, and runoff in the vicinity of Chile and Argentina is decreasing. September 12, 2015.