In October 2011 NASA's Operation IceBridge discovered a gigantic rift in the Pine Island Glacier during research flights over Antarctica carrying radar and lidar equipment for measuring ice thickness. The rift quickly became the focus of international scientific concern, and the crack grew rapidly, with a 280-square-mile chunk of the glacier breaking off to form an island of ice.
NASA says the Pine Island Glacier is one of the largest single contributors to sea level rise in recent years. Shrinking at a rate of 300 feet each year, the glacier is responsible for an incredible 7 percent of the world's recent sea level rise.
This week the German Aerospace Center's Earth monitoring satellite TerraSAR-X confirmed that the rift had run its course, and a large iceberg had indeed broken off of Pine Island Glacier, one of Antarctica's largest, fastest moving, and most important ice streams.
This image of the calving glacier was captured on July 8, 2013, by TerraSAR-X, which has been keeping a close watch on the rift using a radar instrument capable of making observations through even the dark months or heavy cloud cover.