Even in person, it’s hard to appreciate the scale of the Southern Patagonian Ice Field – entire cities would be dwarfed if placed upon the white expanse. From the lookout at Paso del Viento (Windy Pass), vast tracts of jagged, moraine-streaked ice extend towards the horizon, engulfing all but the tallest mountain peaks. Straddling the border of Chile and Argentina, the ice field is one of the largest non-polar glaciers on Earth, stretching along the spine of the Andes for more than 350km. (Credit: Tom Garmeson)
The symbol of Patagonia
The Huemul Circuit begins in the small town of El Chaltén, the undisputed trekking capital of Argentinean Patagonia. The town lies in the shadow of Mount Fitz Roy, an iconic, 3,400m granite peak which separates the ice field from the endless pampas to the east. During the hiking season from October to April, the nearby footpaths throng with people keen to see Fitz Roy’s distinctive summit. (Credit: Tom Garmeson)
Beauty and danger
Ferocious winds, intense precipitation and the risk of falling through a crevasse make exploring the ice field a complicated task. The first recorded north-south crossing didn’t occur until 1998, and getting up close is usually limited to airlifted glaciologists or experienced mountaineers. However, a challenging four-day, 64km hiking trail known as the Huemul Circuit takes intrepid travellers to the edge of the glacier, where panoramic views of this rarely witnessed landscape await. (Credit: Tom Garmeson)
Portal to the pastTo witness the ice field is to stare back in time. Around 18,000 years ago, during the Last Glacial Maximum (LGS), it covered much of South America’s western edge. Today, the Southern Patagonian Ice Field and a smaller, neighbouring glacier called the Northern Patagonian Ice Field are practically the only remnants of the continent’s frozen past, but they remain vitally important. The glaciers act as an enormous reserve of fresh water which nourishes mountain habitats across Patagonia, helping to sustain the region’s diverse plants and wildlife. (Credit: Tom Garmeson)
The great melt
There is still much to learn about Patagonia’s ice fields. A recent study by glaciologists from the University of California, Irvine and partner institutions in Argentina and Chile found that some sections are significantly thicker than was once thought. By measuring subtle changes in the Earth’s gravitational field, they were able to calculate that the ice is upwards of 1,600m deep in parts.
But a warming climate could spell disaster. Many of the outlet glaciers are swiftly retreating, while the ice field itself is thinning out at an alarming rate. A separate study estimated that together, the Northern and Southern Patagonian ice fields shrank by an average of 24.4 gigatonnes per year between 2002 and 2017, the equivalent to almost 10m Olympic-sized swimming pools worth of water. As the Earth continues to heat up, researchers warn that this beautiful and vital natural wonder may not last.
The long-term fate of these frozen giants remains in the balance, but for now, the ice field will continue to silently shape and sustain one of the world’s most pristine environments, as well as enthralling the lucky few who get to see it up close. (Credit: Tom Garmeson)
Tongues of ice
The ice field may span around 13,000 sq km, but it’s surprisingly elusive. Hemmed in by snow-drenched peaks on all sides, this glacial behemoth only reveals itself to the outside world by spilling out through the surrounding mountain valleys. Tourists who flock to Chile’s Grey Glacier and Argentina’s famous Perito Moreno Glacier are in fact witnessing tendrils from the ice field as it reaches down towards the Patagonian flatlands. (Credit: Tom Garmeson)
Shades of blue
To the ice field’s west lie the labyrinthine fjords of Chile’s Patagonian archipelago, while in Argentina to the east, outlet glaciers (valley glaciers that drain an inland ice sheet) carve their way through mountain passes to unload into several great lakes, each a different shade of turquoise. The tree-lined edge of Lago Viedma provides welcome refuge for campers after descending from Paso del Viento. From time to time, the stillness of the lake is interrupted by the thunderous crack of calving icebergs, causing waves to roll all the way to shore. (Credit: Tom Garmeson)