With today’s image of the week we want to transport you to Patagonia to look at a unique fresh-water calving glacier – Perito Moreno in Argentina. This is a hot topic at the moment as the glacier did something rather unusual yesterday, read on to find out more…..
This large glacier (Fig 2, highlighted red) flows down a valley, calving into the southwestern arm of Lago Argentino at its terminus. However, at times the glacier front advances far enough to connect with land on the opposite bank of Lago Argentino. This cuts off the flow of water from Brazo Rico (Fig 1., left), into Lago Argentino (Fig 1., right) acting as an ice dam.
The ice dam can reach hundreds of meters in height and can cause the water level in Brazo Rico to rise up to 30 m above that of Lago Argentino. Eventually the dam collapses, accompanied by rapid collapse of the ice front and the water rushes through, equalising water levels. The glacier then continues to advance and the cycle repeats.
These collapse events appear to happen every few years, with the last event happening YESTERDAY – March 10th 2016 (see the video link). The length of a cycle is very unpredictable and it is unclear exactly what is controlling the ice dynamics in this region. Naruse and Skvarca, 2012 made a comprehensive study of the 2003-2004 ice dam formation and collapse but more information is needed to fully understand this complex glacier.