Aconcagua

Aconcagua is a giant mountain in South America.

It is the tallest mountain in the Americas. It is part of the long Andes mountains. Its top has two peaks joined by a long ridge. The air up there is thin and cold.

Aconcagua rises in the Andes, in the province of Mendoza in western Argentina, right next to the border with Chile. Britannica says that although its peak is in Argentina, its western slopes rise from the lowlands of Chile, just north of the city of Santiago. It is the highest point in the Western Hemisphere, the half of the world that includes North and South America.

The mountain has two summits, north and south, joined by a ridge about 1 kilometer long called the Cresta del Guanaco. The north summit is the higher one. Its height has been measured in different ways, which gave slightly different answers: about 6,959, 6,961 or 6,962 meters, depending on the survey.

Britannica places Aconcagua in western Mendoza province, west-central Argentina, on the Chilean border, in the Southern Andes, with its western flanks building up from the coastal lowlands of Chile just north of Santiago. It notes that the precise elevation has been debated since the early 20th century: the Military Geographical Institute of Argentina documented 6,959 m, long in general use; a 2001 GPS survey led by Italian geologist Giorgio Poretti reported 6,962 m ± 5 m, not officially recognized; the south summit measures 6,930 m.

In September 2012, an expedition sponsored by Argentina's National Geographic Institute (IGN) and CONICET's Sigma project announced a new official height of 6,960.8 m, measured with gravimetry, which references height to sea level unlike GPS alone. The earlier official value, 6,959.6 m, dated from a 1956 University of Buenos Aires survey; IGN scientist Sergio Cimbaro stressed the two were not comparable because the methods differ, and the team installed a GPS station on the mountain to monitor the Andean crust from then on.

The land around Aconcagua is high and dry.

Tough little plants grow between the rocks. Big birds called condors soar over the mountains. Guanacos, relatives of llamas, live in the Andes too.

This part of the Andes is very dry. Britannica says that in this stretch of the Andes the mountains become more arid and higher, and glaciers are rare, found only at the highest levels. Plants and animals live at different heights, and nothing lives above the permanent snow line.

The Andes are home to the Andean condor; Britannica says it is thought to fly as high as about 7,900 meters. Pumas, guanacos and vizcachas also live in parts of the Andes. In the Aconcagua park, rules protect this wildlife: visitors may not remove plants, rocks or fossils, or light fires.

Britannica describes how Andean plant and animal communities change with altitude, with the permanent snow line the upper limit of habitation; cats rarely live above about 4,000 m, white-tailed mice range from about 4,000 to 5,200 m, and camelids such as the guanaco are mainly animals of the high plateaus. The condor is thought to fly up to about 26,000 ft (about 7,900 m). In the dry southern Cordillera Occidental, Britannica lists guemul, puma, vizcacha, chinchilla, camelids, mice and lizards, with condors among the birds.

Around Aconcagua the Central Andes become arid and high, and glaciers are rare except at high elevations. Mendoza province manages Aconcagua as a provincial park within its system of protected natural areas, stating the aim of protecting the environment, its flora and its fauna; park rules forbid fires and the removal of vegetation, firewood, fossils or rocks, and require visitors to keep to marked trails.

People tried to climb Aconcagua for a long time.

In 1897 a climber named Matthias Zurbriggen reached the top. Now many climbers come every summer. Scientists climb it too, to measure how tall it is.

The first attempt to climb Aconcagua, in 1883, did not succeed. In 1897 the Swiss climber Matthias Zurbriggen became the first person to reach the north summit. Today Aconcagua is in a provincial park run by Mendoza province. Its 2023-2024 summer season opened on 1 November, and 900 permits were sold ahead of time, most of them to visitors from other countries.

Scientists climb it too. In 2012 an expedition backed by Argentina's National Geographic Institute carried instruments to measure the mountain's height and to study its glaciers and the moving plates. The climb was hard even for them: the team had serious trouble adjusting to the thin air above 4,500 meters, and not everyone reached the top.

Britannica records a failed first attempt in 1883 and the first ascent of the higher north summit in 1897 by Swiss climber Matthias Zurbriggen. Britannica also notes that the name may come from Quechua, possibly meaning 'Sentinel of Stone'.

Mendoza's government opened the 2023-2024 summer season of Aconcagua Provincial Park on 1 November, with a season running to 30 April; access tickets are bought online and carried with identification. That season's presale issued 900 permits (860 for climbs, 30 for short and 10 for long treks), 730 of them to foreign visitors. The 2012 IGN-CONICET expedition combined its height survey with glacier and plate monitoring; EFE reported that members faced severe acclimatization problems above 4,500 m and that some, including IGN scientist Sergio Cimbaro, had to descend before the summit.