I just returned from an assignment in Patagonia.  The last day we visited the Perito Moreno Glacier in the Los Glaciares National Park near El Calafate, Argentina.  The weather was beautiful and warm.  We noticed a lot of glacier calving probably caused by the warm sunshine.  One of the huge blocks of ice got our attention, because smaller blocks of ice were constantly breaking off of the base of this tower of ice.  We kept watching it and after about 30 minutes it happened:  larger and larger pieces of ice broke off and it started to lean and finally falling over making a huge splash.  Here are some of my photos and the video was taken by Mary Jo Smith.

Here is a link to the video Mary Jo Smith took of this glacier calving: