The Southern Patagonian Ice Field is the third largest in the world and the most important source of freshwater in South America. It covers 5,000 square miles (85 percent of which are located in Chile, and 15 percent in Argentina) and is the birthplace of 48 large named glaciers, including the famously still-advancing Perito Mereno and the Viedma Glacier—the largest in Argentina. Viedma, like Perito Moreno and many others, is located within the UNESCO-protected Los Glaciares National Park. Viedma is best accessed from the small town of El Chaltén.
The iceberg flows down the valley and calves at its terminus, an area that is referred to as “moraine-rich,” which means ice picks up silt as it goes and is dusted with grey and black on exposed surfaces, as opposed to being pristine and white. Within the glacier, as moraine turns and moves, it is also visible as dark stripes, showing the movement the ice took as it came down the valley.
The ice chunks that fall from Viedma Glacier drop into and make up the western end of Viedma Lake. A boat ride on the lake provides the best view of the glacier, with Mount Fitzroy and Mount Huemul in the background. And if want to get out on the glacier, you can head out on an ice trek with crampons and an ice ax.