Perito Moreno Glacier

A wall of ice creeping across a lake

Perito Moreno is a huge river of ice 30 km long that slowly slides from the mountains into a lake — 2 metres a day! The ice wall facing the lake is 70 metres high; chunks keep breaking off with a roar and crashing into the water — that's what tourists come to watch. The ice splits the lake in two and forms a 'dam'; every few years the water bursts through it with a deafening crash.

Perito Moreno is a 250 km² glacier flowing from the Southern Patagonian Ice Field (the world's 3rd largest after Antarctica and Greenland) into Lake Argentino; 30 km long, with a 5 km wide front rising 70 m above the water (170 m total thickness). It moves 2 m a day — fast for a glacier. One of the few glaciers in balance: despite warming it has barely retreated since 1917 (heavy precipitation plus a steep bed). The ice pushes against a peninsula and dams the Brazo Rico arm; the water rises 30 m, then the ice dam collapses (1917, 1988, 2004, 2016…) — the 'rupture'. Los Glaciares National Park (UNESCO, 1981) offers walkways and ice trekking. Named after the 19th-century explorer Francisco Moreno.

Fun facts

• The glacier moves 2 metres a day — you can watch it happen.
• Despite warming, Perito Moreno has barely shrunk in 100 years.
• The ice dam collapses every few years with a thunderous roar.