The Northern Patagonian Ice Field (NPIF), centered near 47degS, 73.5degW, is the smaller of two remnant ice masses crowning the Andes Mountains of lower South America. The NPIF is a vestige of an extensive ice sheet that covered much of Patagonia just over a million years ago. Today, with its glaciers largely in retreat and only an area of 4,200 sq km, it is still the largest continuous mass of ice outside of the polar regions. Survival is based on its elevation (1, 100 to 1,500 m), favorable terrain, and a cool, moist, marine climate. The ice field has 28 exit glaciers, the largest two--San Quintin and San Rafael--nearly reach sea level to the west at the Pacific Ocean. Smaller exit glaciers, like San Valentin and Nef, feed numerous rivers and glacially carved lakes to the east.
This photo taken by the crew of STS-108 in December, 2001, offers a remarkably clear view of the northern two-thirds of this bright, icy feature, its glaciers, and its northern and eastern flanks. Arms of Lake General Carrera are visible on the right of the image. Such photos offer unsurpassed visual context information about the state of this remote locale and details of its features and processes.