Glaciar Perito Moreno - Upper View

The pressure caused by the trapped mass of water eventually becomes untenable for the glacier (or rather, the melting ice below it), and as the water filters through the ice, causing fractures and hollowing it out, inevitably, the dam collapses in a spectacular detonation of water and ice. Unfortunately, it is not always possible to predict when the caving in of the dam is likely to occur, nonetheless, many visitors go there with the hope that they will be lucky enough to witness this unique cataclysmic event, at a time when the situation is "ripe".