The massive crack running through Antarctica’s fourth-largest ice shelf dramatically accelerated its growth last month, extending over 11 miles in just six days. According to the UK-based Project Midas research group, the 110 kilometer (68 mile) long chasm extended an additional 17 km (11 miles) between May 25 and May 31.
The crack’s course has also suddenly turned seaward, with only 13 km (8 miles) remaining before the ice front calves off. Provided the ice front stays intact after calving, the resulting iceberg would account for more than ten percent of Larsen C’s area, a 5,000 square kilometer (1,150 sq mi) island of ice 350 meters (1,150 feet) thick, approximately the size of the state of Delaware. A berg that size would be one of the largest on record.
While the calving of an iceberg of this nature won’t contribute to sea level rise, as the Larsen C ice shelf is already in the water, researchers are concerned about what this means for the stability of the rest of the ice shelf behind it. The ice that makes up ice shelves like Larsen C originate from land-based glaciers, with the shelves themselves acting as plugs that keep the glaciers from flowing too quickly into the ocean. If the ice shelf itself disintegrates, that could trigger a rapid flow of the glacier behind it into the ocean, as it was in the case of the breakup of the Larsen B shelf in 2002, causing the Crane Glacier behind it to increase the speed of its flow threefold.