The Mighty Andes

The Patagonian Desert in South America lies in the rain-shadow of the mighty Andes Mountains that run parallel to the western edge of the continent. revailing winds in this temperate area, some 40 to 50° south, are from the northwest and gradually lose their moisture content over the high Andean peaks, many of which approach 4,000 meters (13,000 ft.) in altitude. Cool, dry winds—known as pamperos—sweep down the western Andes foothills at an altitude of about 1,500 meters (4,900 ft.), and across the Patagonian plains. Their moisture evaporated, they carry away any rain that has fallen, thereby accentuating the drying effect of the Andean rain-shadow.