The Andes Mountains region of South America is known as the Avenue of the Volcanoes. Thousands of volcanoes are scattered throughout the 4500-mile (7200-kilometer) length of the Andes from Panama to the southern tip of Chile (Tierra del Fuego). This photograph shows two major snowcapped volcanoes in the Arequipa Department of southern Peru. Southernmost Ampato Volcano rises more than 20 700 feet (6310 meters) above sea level. A vent developed on the northeast side of Ampato Volcano where a flank eruption occurred, as evidenced by the extensive, darker lava flow, which is almost always indicative of more recent flows. Many of the volcanoes exhibit the pronounced, classic, radial drainage pattern. The deeply shadowed canyon northwest of Ampato Volcano is part of the Colca River Valley, whose river eventually empties into the Pacific Ocean. Most of the rivers flowing through this part of Peru are short and flow intermittently. This mountainous region is part of the Western Cordillera where the climate is extremely arid, with most areas receiving less than 10 inches (25 centimeters) of precipitation annually; therefore, vegetation is sparse. The Peruvian coastal mountains are under the influence of a dry air mass that is stabilized by the cold Peru Current.