Dark clouds hang dramatically in the sky, contrasting with soaring white cliffs streaked with deep blue and rising high above a turquoise lake. The smell of ice hangs in the air, as does the creaking, rolling sound of ice on the move. Occasionally that sound rises to a crashing boom as huge chunks break off and hit the lake's surface.The expanding glacier slowly but steadily creeps over the deep lake (Lake Argentino) until it effectively cuts it in two. The water on one side of the lake then builds up with nowhere to go. Eventually the increasing pressure from the extra water ruptures the ice, often in a spectacular fashion. One lucky park ranger who has witnessed this rupture twice described it as being like “a massive building falling of [a] sudden.”
The first rupturing of the ice by water pressure occurred in 1917. The burst was so strong at that time that it washed away a nearby ancient forest of beech trees. Since then the ice ruptures about every four to five years, although it is far from regular.
Commenting on the glacier's continued growth, Andres Rivera, a glacialist from the Center for Scientific Studies in Valdivia, Chile, says, "[W]e're not sure why this happens but not all glaciers respond equally to climate change."
The Patagonian ice cap that the Perito Moreno glacier stems from is enormous. It resides on the border of Chile and Argentina and covers an area of 600,000 hectares. The Argentinian part of this area is home to 356 glaciers, and out of these Perito Moreno is the most well known and most visited by tourists. In fact, it's pretty safe to say that it’s the most famous glacier in South America!This is Argentina's Perito Moreno glacier, remarkable both because it is the world's third largest source of freshwater, and because — despite global warming — it is still growing. One of 48 glaciers fed by the Southern Patagonian Ice Field, Perito Moreno is currently about 197 feet (60 m) high and 3 miles (5 km) wide.




 This continued growth is especially perplexing in light of what is happening to most of the other Andean glaciers (and indeed glaciers worldwide) that are melting at increasing rates. Scientists have also reported that ice-loss in the Patagonian region is ten times the long-term average.

Despite continually having giant icebergs carved out from its midst, the Perito Moreno manages to keep up its production of new ice. The ice river is constantly growing and moving, changing its shape and the shape of the land around it. This may also be due to warming, however. A warmer climate generally means more rainfall, which can actually increase a glacier's size.