Perito Moreno Glacier in southern Andes Mountains

The photo above shows the sculptured blue ice of Perito Moreno Glacier in the southern Andes Mountains, near Santa Cruz, Argentina. This scenic glacier is the main attraction of Parque Nacional Los Glaciares.  Photographer Hector Fabian Garrido

It’s but one of nearly 50 glaciers fed by the Southern Patagonia Ice Field. Although glacier recession has been noteworthy in southern Patagonia during the past three decades, Perito Moreno has actually been growing — ice formation in the high mountains is somewhat greater than ablation at lower elevations and calving into Lago Argentino.



The foreground ice appears turquoise because the longer wavelengths of light (reds and oranges) are extinguished by thick ice; only the shorter wavelengths (blues and greens) emerge. The thicker the ice, the bluer it looks — the longer light travels through it. Fresh snow has little or no coloration since, in contrast to thick ice, sunlight barely penetrates its surface.

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