Landsat 7 data, acquired by the U.S. Geological Survey, show the break of a large ice unit in the Petermann Glacier in northwestern Greenland.
Scientists have been predicting the break for over a year; a June 26 acquisition shows the ice still in one large unit, though field sensors detected large cracks developing. The August 13 image shows the large unit (roughly 40% larger than the area of the District of Columbia) after it has broken away. The unit that broke off is the largest piece to break away in the Arctic ice since 1962. Warmer water temperatures below the floating ice and warmer sea surface temperatures are probable causes for the break.
Landsat data will provide useful information on the development of smaller units in the near future. Most of the break away ice will freeze in place with the coming winter; however, smaller units will be monitored as they drift into shipping lanes.