A 76-Square-Kilometer Greenland Iceberg Hit an Island—and Stayed Intact

A giant iceberg from Greenland’s Petermann Glacier struck a small rocky island in August but did not break apart, according to reporting based on NASA Earth Observatory material. The flat-topped ice island separated from Petermann Glacier on August 4, 2026. Researchers estimated its area at just over 76 square kilometers (29 square miles), roughly comparable to the size of St. Thomas in the U.S. Virgin Islands. The event was described as the largest calving from an Arctic glacier since 2020 and the biggest Petermann calving since 2012, when a roughly 130-square-kilometer ice island broke free. Adam Garbo, a doctoral student in glaciology at the University of Ottawa, identified the break using imagery from the European Space Agency’s Sentinel-1 mission. Researchers had been watching several major cracks in Petermann’s floating ice tongue and had expected a larger section to detach. Instead, the glacier fractured along a different crack, producing the smaller of the anticipated ice islands. After leaving the glacier, the iceberg traveled down Petermann Fjord at an average speed of about 3 kilometers per day during its first week. It then reached Joe Island, also known as Joe Ø, near the fjord’s entrance to Nares Strait. Landsat 9 images captured the iceberg’s encounter with the island on August 23 and 24. Collisions at Joe Island can damage icebergs. A Petermann ice island that struck the same outcrop in 2010 split into two pieces. The 2026 iceberg, however, remained intact. Satellite observations later showed it pivoting away from the island and moving southwest through Nares Strait, carried by winds and surface currents. The iceberg was estimated to be less than 150 meters thick when it broke away. Researchers expect tides, winds, currents and melting to weaken it over time, eventually causing it to fragment. Petermann ice islands can travel long distances through Arctic waters, where they may create hazards for ships, marine operations and infrastructure. Their melting also releases freshwater into the surrounding ocean.