English: The Andes form the rugged backbone of South America, spanning about 4,500 miles (7,242 km) and seven countries. Snow caps the southern Andes year-round and the snowpack that accumulates in the mountains each winter is the primary source of water for the surrounding countryside, including the communities found at lower altitude. Streams filled with the spring snow-melt deliver the water to central-western Argentina and central Chile for use in drinking water, power generation, and agriculture.

The Moderate Resolution Imaging Spectroradiometer (MODIS) aboard NASA’s Terra satellite acquired a true-color image of the southern Andes on June 11, 2017.

The bright autumn day shows the snow in bright-white reflection from Bolivia in the north to Argentina (east) and Chile (west). Light cloud covers the snow in a few spots, particularly in the northern third of the mountain range. In the far north the wide, smooth, and highly-reflective white patches are not snow. This is the Salar de Uyuni, the world’s largest salt flat. It measures about 4,086 sq. mi (10,582 sq. km) and sits in the high Andes at an elevation of 11,995 feet (3,656 meters) above sea level.

A large bank of marine stratocumulus clouds covers the South Pacific Ocean. It gives way to low cloud (fog) that stretches over the coastline. In some areas in southern Chile, fingers of fog fill the valleys of the foothills of the Andes Mountains.