The high plateau region (altiplano) of western Bolivia and southern Peru, averaging about 12 000 feet (3650 meters) above sea level, and its associated basin are bordered by the Cordillera Oriental to the east and the Cordillera Occidental to the west. The details in this southwest-looking photograph are typical of the nonvegetated, generally flat, arid surface of the altiplano in southwestern Bolivia. The altiplano’s high, encircling mountain ranges, formidable physical barriers to weather systems, allow very limited quantities of precipitation during the summer months. The north-to-south drainage pattern shows flow into Lake Coipasa from the intermittently flowing Lauca River and its many tributaries. Along the western third of the photograph is a very pronounced volcanic landscape comprising individual volcanoes and clusters of volcanoes, which in terms of density and altitude are fairly typical of many areas of the Cordillera Occidental. The volcanic peaks range from 16 000 feet (4900 meters) to more than 19 000 feet (5800 meters). Even though Lake Coipasa had water when this photograph was taken, it is frequently called Salar (dry lakebed) de Coipasa because of insufficient flow from the river. Evaporation is a major cause of water loss for the entire region. (See photograph SL3-115-1911 for a synoptic view of this same general area in which Salar de Coipasa is a much smaller lake with very little water. Based on reviews of recent Shuttle photographs, this area of the altiplano seems to be experiencing at least a short-term drought because little or no water can be seen in the dry lakebeds.)