Set in Santa Cruz Province in southern Argentina, Perito Moreno Glacier flows from the immense Southern Patagonian Ice Field into Lago Argentino. Long famous as an exception among Patagonia’s retreating glaciers, its remarkable stability has recently begun to change. For much of the twentieth century, the glacier repeatedly advanced against the Magallanes Peninsula, damming Brazo Rico and creating a spectacular ice bridge that eventually collapsed — historically at intervals averaging around four years, although the cycle was highly irregular. The last full ice-bridge collapse occurred in December 2019, and there has been no comparable rupture since. As the glacier now thins and retreats, it may be losing the conditions that enabled this famous cycle. Whether the great ice bridges will return remains uncertain, but Perito Moreno’s immense fractured ice front, vivid blue ice and thunderous calving remain among Patagonia’s most extraordinary sights.
A sense of scale
The scale of Perito Moreno is surprisingly difficult to judge from photographs. The ice cliffs at the glacier’s edge rise around 60–70 metres above the lake, yet without something familiar for comparison they can appear much smaller. It was only when a large sightseeing boat passed in front of the glacier that the scale became obvious. Even the icebergs scattered across the lake, which can be tens of metres across, seemed modest against the vast wall of ice.
Among the ice
Closer to the glacier, its surface resolves into a chaotic landscape of pinnacles, ridges and deep blue fractures. From a distance these features can appear almost delicate, but up close their scale is extraordinary. In places, individual formations tower above the people crossing the ice, while layers of compressed ice create increasingly intense shades of blue within the deeper crevasses.
Ice, light and form
Seen more closely, the glacier becomes a landscape of constantly changing shapes and colour. Jagged walls give way to sculpted forms, while the ice shifts from almost white to vivid turquoise and deep blue as the light and density change. Even fragments floating away from the glacier can be enormous, their true scale almost impossible to judge in the open water.
A landscape in motion
For all its immense scale, Perito Moreno is anything but static. The glacier creaks and fractures as the ice moves towards its terminus, occasionally sending sections of the towering face crashing into the lake. During our visit we witnessed two significant calving events. The collapse was spectacular, but it was the sound — the crack of breaking ice followed by a deep roar across the water — that most vividly conveyed the forces at work.
During our visit to Perito Moreno Glacier, we were fortunate to witness two significant calving events. This video captures the larger of them, as a substantial section of the glacier’s towering ice front breaks away and crashes into Lago Argentino. The scale is difficult to convey in photographs alone; the movement and tremendous sound of the collapsing ice bring the glacier vividly to life.
