RADARSAT-1 satellite imagery recently revealed that the Ward Hunt Ice Shelf, located on the north coast of Ellesmere Island in the Canadian territory of Nunavut, has ruptured. As a result, the Northern Hemisphere's largest epishelf lake has been drained. The "lake" was a 43 meter-deep layer of fresh water stratified over a 360 meter-deep layer of denser ocean water that was dammed behind the Ward Hunt Ice Shelf. With the draining of the ice-dammed epishelf lake, a unique ecosystem containing rare plankton and other life was lost.

As shown in the images on this page, the rupture (red) in the Ward Hunt Ice Shelf (area delineated in blue) can be easily located. In Standard Beam Mode (25-meter resolution) RADARSAT-1 acquired the top image on Sept. 27, 2003. The scale bar represents 10 kilometers on the ground. As shown in the image at right, the rupture in the ice shelf becomes even more apparent in Fine Beam Mode (8-meter resolution). This image also was acquired Sept. 27, 2003.

Scientists at Laval University in Quebéc and the University of Alaska at Fairbanks have been monitoring the fracturing of the ice shelf during the last few years using RADARSAT-1 and field observations. In a RADARSAT-1 image acquired in 2000, the scientists noted the beginnings of fracturing on the ice shelf. During the next months, subsequent imagery showed that the number and size of the fractures was increasing. This resulted in the eventual split of the ice shelf into two major pieces by 2002.

The scientists believe that the breakup and disintegration of the Ward Hunt Ice Shelf can be attributed to warming temperature trends that began in the 19th century. Climate change models support this supposition, as polar regions show some of the greatest changes as a result of global warming.

Images courtesy: RADARSAT International

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