Rupturing of Perito Moreno Glacier Bridge

February 05, 2013


Photographer: Christian Grosso
Summary Authors: Christian Grosso; JIm Foster

As the massive tongue (covering 97 sq. mi or 250 sq. km) of the Perito Moreno Glacier, in the Santa Cruz province of Argentina moves forward it cuts off the Brazo Rico arm of Lago Argentino. The blocked water slowly builds up pressure undermining the ice and eventually forming a cave or tunnel. Over a period of 10 to 50 months, the resulting ice bridge fails crashing into the frozen lake and upon its shore. This phenomenon repeats itself at irregular intervals, with the last two major ice collapses occurring in 2012 and 2008. I was one of perhaps 20 privileged people in Los Glaciares National Park this midsummer day to witness the spectacle. Note the robins' egg blue color of the jagged ice face (see yesterday's Earth Science Picture of the Day). Photo taken on January 19, 2013.

Photo details: Camera Model: Canon EOS 7D; Lens: EF35-350mm f/3.5-5.6L USM; Focal Length: 80.0mm; Aperture: f/5.0; Exposure Time: 0.0003 s (1/4000); ISO equiv: 400; Exposure Bias: -0.33 EV; Software: Adobe Photoshop Camera Raw 7.3 (Windows).