Lago Argentino is the largest and southernmost lake in Patagonia, Argentina, at the southernmost tip of the Andes. This lake is unique because of the spectacular glaciers that plunge directly into its waters, such as the Perito Moreno glacier and the Upsala glacier. It covers an area of 1,560 km² – more than three times the size of Lake Geneva – and plunges to a depth of 500 metres. As a result of global warming, these fabulous glaciers are threatened with extinction before the end of the century.
Los Glaciares National Park – a UNESCO World Heritage Site – is the jewel in the crown of a gigantic ice field in southern Patagonia, a veritable sea of icy freshwater covering almost 17,000 km2 (straddling Argentina and Chile).
It’s the world’s third-largest ice cap, after Antarctica and Greenland.
On a per-unit-area basis, Patagonia now has the highest rate of glacier melt in the world. Patagonia has so many glaciers, and the melting is so pronounced, that after Alaska, it’s the region that contributes most to rising sea levels.
But there’s another, lesser-known phenomenon in the region. The ground rises: this is called post-glacial rebound (or isostatic adjustment). When glaciers melt, these huge quantities of stored water flow into the ocean, removing the enormous weight that crushed the soil. Up to 4 cm per year, which is unique.
As a result of these transformations, all of Patagonia’s landscapes are changing.
The Perito Moreno is probably the most famous glacier in the region, occupying the entire width of the Lago Argentino, from one shore to the other, and the tongue of ice is well anchored, so that it forms a natural dam.
A rare phenomenon has been attracting attention for several years.
Large quantities of water from the Andes flow beneath the glacier. And because of this natural dam, meltwater from the south raises the glacier level up to 30 meters above the lake. The high pressure exerted by this water eventually causes large chunks of glacier to break off and collapse with a great crash. The process repeats itself every four or five years as the ice is pushed back to the opposite shore.
These spectacular breaks have made the glacier and lake a major tourist attraction in the region, and one of the symbols of the melting ice caused by global warming.
