Los Glaciares National Park

Lore & Background

The park's name refers to the giant ice cap in the Andes, the Southern Patagonian Ice Field, which is one of the largest outside of Antarctica, Greenland, and Iceland, though ice caps in the Canadian Arctic (e.g., Ellesmere Island) are larger. It feeds 47 large glaciers, of which 13 flow towards the Pacific Ocean. Due to the size of the ice cap, these glaciers begin at only 1,500 m above mean sea level, sliding down to 200 m. The park can be divided into two parts, each corresponding to one of the two elongated big lakes partially contained by the park: Lake Argentino in the south and Lake Viedma in the north. Between the two halves is a non-touristic zone without lakes called Zona Centro. The northern half includes Mount Fitz Roy and Cerro Torre, popular for climbing and trekking. The southern part features major glaciers including Perito Moreno Glacier, Upsala Glacier, and Spegazzini Glacier.

Reader's Guide

Los Glaciares National Park is significant as a UNESCO World Heritage Site and the largest national park in Argentina, preserving a representative sample of Magellanic subpolar forest and west Patagonian steppe biodiversity. Its giant ice cap is the largest outside Antarctica, Greenland, and Iceland, feeding 47 glaciers that are unusually low-lying due to the ice cap's size. The park faces issues including overgrazing, forest fires, and invasive species such as cattle, European hares, and certain types of trout. It is a major attraction for international tourists, with starting points at El Calafate and El Chaltén. The park also served as a filming location for the documentary series The Future is Wild. Its legacy includes ongoing conservation challenges and its role as a key site for understanding glacial and Patagonian ecosystems.

Did You Know?

• The park covers 726,927 hectares, making it the largest national park in Argentina.
• It was declared a UNESCO World Heritage Site in 1981.
• The park's ice cap is one of the largest outside Antarctica, Greenland, and Iceland, though ice caps in the Canadian Arctic are larger.
• Perito Moreno Glacier is reachable by land, while Spegazzini and Upsala glaciers are accessible by boat.

The Glacial Heart and Dual Lake System

Los Glaciares National Park spans 726,927 hectares in Santa Cruz Province, making it Argentina's largest national park. About thirty percent of that territory is locked in ice, fed by the massive Andean ice cap—the greatest one outside Antarctica, Greenland, and Iceland. This cap sustains forty-seven major glaciers, thirteen of which drain toward the Pacific. Because of the cap's extraordinary volume, these ice rivers begin their descent at just 1,500 metres above sea level and slide down to 200 metres, far lower than the 2,500-metre starting points typical of glaciers elsewhere.

The park divides naturally into two elongated halves around a central, non-touristic corridor called Zona Centro. In the south, Lake Argentino spreads over 1,466 square kilometres—the largest body of water in the country—and receives the flows of Perito Moreno, Upsala, and Spegazzini glaciers. In the north, Lake Viedma covers 1,100 square kilometres alongside the Viedma Glacier and the iconic peaks of Mount Fitz Roy and Cerro Torre. Both lakes ultimately drain into the Santa Cruz River, which carries their waters eastward to the Atlantic coast at Puerto Santa Cruz.

Rain Shadow, Forest, and Fauna

The Andean range acts as a massive moisture barrier, capturing most Pacific Ocean humidity on its western face and passing only cold air to the Argentine side. This rain-shadow effect creates the arid Patagonian steppe dominating much of the park's eastern landscape, where the annual average temperature hovers near 7.5 °C. Despite the harshness, this steppe supports rheas, guanacos, cougars, and the South American gray fox. The gray fox has been pushed toward endangerment by cattle-industry encroachment, while the guanaco, though not yet classified as endangered, has suffered a dramatic historic decline largely attributable to large-scale livestock grazing throughout Patagonia.

Between the ice fields and the steppe lies a fertile band of Magellanic subpolar forest, dominated by lenga and guindo trees with scattered ñires. This more hospitable zone shelters huemul deer and the torrent duck. Above it all, more than one hundred bird species—including condors and eagles—circle the peaks. In 1981, UNESCO recognized this remarkable mosaic of habitats by designating the park a World Heritage Site, affirming that a representative sample of both Magellanic subpolar forest and west Patagonian steppe biodiversity remains in good conservation condition within its boundaries.

Climate and the Ice Cap's Vertical Reach

Los Glaciares enjoys a cool, moist temperate climate, yet the range of conditions within its borders is striking. Mean temperatures swing from 0.6 °C in winter to 13.4 °C in summer at lower elevations, while at higher altitudes the annual mean can dip to around −3 °C. Rainfall, distributed fairly evenly across the year, averages 500 millimetres in the western part of the park and 900 millimetres in the east, and snowfall is a regular feature of the colder months.

The park's most remarkable physical feature is the vertical reach of its glaciers. In most parts of the world, glaciers do not begin their flow until they sit at least 2,500 metres above sea level. Here, the sheer mass of the Andean ice cap allows the ice to start moving at just 1,500 metres and to slide all the way down to 200 metres before calving into the lakes below. This extraordinary low-altitude flow makes the park's forty-seven glaciers unlike anything found on other continents, and it is precisely this spectacle that draws excursion boats threading between icebergs to Onelli Bay and the otherwise inaccessible shores of Spegazzini and Upsala, while Perito Moreno remains reachable by land.

Threats to a Fragile Landscape

Despite its protected status, Los Glaciares faces a growing catalogue of pressures. Overgrazing remains a serious problem in certain areas, and the landscape has been invaded by alien and feral species—cattle, European hares, and certain non-native trout—that compete with or prey upon native wildlife. The South American gray fox has been driven to endangered status by the spread of the cattle industry, and the guanaco, though not yet classified as endangered, has experienced a dramatic historic collapse largely attributable to large-scale livestock grazing throughout Patagonia.

Forest fires have also struck the park with considerable force, degrading and destroying sections of the Magellanic subpolar forest between the ice fields and the steppe. Tourism, while economically vital, adds its own strain to an ecosystem already under stress. The park's administration is headquartered in El Calafate, on the shore of Lake Argentino just outside the park boundary, while El Chaltén village in the northern section, at the foot of Mount Fitz Roy, serves as another gateway for visitors. Even the park's glaciers are not immune to change: a famously stable glacier within the park has thinned considerably since 2019, a reminder that the ice defining this landscape is far from permanent.