The Cordillera Blanca (Spanish for "white range") is a mountain range in Peru that is part of the larger Andes range and extends for between 8°08' and 9°58'S and 77°00' and 77°52'W, in a northwesterly direction. It includes several peaks over high and 722 individual glaciers. The highest mountain in Peru, Huascarán, at high, is located there. The Cordillera Blanca lies in the Ancash region and runs parallel to the Santa River valley (also called Callejón de Huaylas in its upper and midsections) on the west. Huascarán National Park, established in 1975, encompasses almost the entire range of the Cordillera Blanca. Snowmelt from the Cordillera Blanca provides part of northern Peru with its year-round water supply, while 5% of Peru's power comes from a hydro-electrical plant located in the Santa River valley. The area of permanent ice cover shrank by about a third between the 1970s and 2006. Geography The Cordillera Blanca is the most extensive tropical ice-covered mountain range in the world and has the largest concentration of ice in Peru. It is part of the Cordillera Occidental (the westernmost part of the Peruvian Andes), and trends in a northwesterly direction for 200 km between 8°08' and 9°58'S of latitude and 77°00' and 77°52' W of longitude. It has five of the most spectacular peaks above 6,000 m in the Peruvian Andes; the highest peak, Huascarán, rises to an elevation of 6,768 m above sea level. The Cordillera Blanca also acts as a continental divide: the Santa River on the west drains into the Pacific Ocean, whereas the Marañón River on the east drains into the Atlantic Ocean. Glaciers Until the 1990s a total of 722 individual glaciers were recognized in this mountain range, covering an area of 723.4 km2. Most were on the western side of the range, where 530 glaciers covered an area of 507.5 km2, while on the eastern side 192 glaciers covered an area of 215.9 km2. Most of the glaciers, 91% of the total, were classified as mountain glaciers (they are generally short and have extremely steep slopes); the rest were classified as valley glaciers, except for one ice cap. Like all Andean glaciers, the Cordillera Blanca has witnessed a major retreat of its glaciers during the 20th century due to global climate change. Studies have shown a retreat of over 15% since the 1970s. Based on analysis of satellite imagery, in 2003 there