A Monumental Break
A colossal iceberg, roughly the size of Manhattan Island, has broken free from Greenland's Petermann Glacier. The newly separated tabular iceberg, which may be as much as 150 meters thick, calved from the glacier's floating ice tongue, according to scientists tracking the event.
This is the largest calving event at Petermann Glacier since 2012, underscoring the dynamic nature of Greenland's ice sheet.
Years in the Making
The break was first identified by Adam Garbo, a PhD student in glaciology at the University of Ottawa's Department of Geography, Environment and Geomatics. He and an international team have been monitoring Petermann Glacier with satellite observations since 2019, closely watching the expansion of fractures in the ice tongue.
"Petermann Glacier has long been one of Greenland's largest remaining ice tongues," said Garbo. "We've anticipated this break for years, and seeing it finally happen is remarkable."
The team's vigilance paid off. Images from the European Space Agency's Sentinel-1 mission revealed clear signs of deterioration along the centerline of the ice tongue on August 3. By 20:00 UTC on August 4, the ice island had fully separated from the glacier's eastern side.
A Rare Arctic Phenomenon
While large, flat-topped icebergs are relatively common in the Southern Ocean surrounding Antarctica, comparable ice islands are far rarer in the Arctic. Their scarcity and longevity make them particularly valuable to researchers studying glacier retreat, ocean circulation, and the hazards posed by drifting ice in polar shipping lanes.
The discovery is part of an ongoing collaboration involving the University of Ottawa, the University of Stirling, Environment and Climate Change Canada, Lancaster University, and the University of Leeds.
Monitoring the Drift
Environment and Climate Change Canada is now tracking the movement of the new ice island, assessing potential risks to vessels and offshore operations in the region. While the calving itself is a natural event, scientists say it provides a rare opportunity to observe how massive Arctic ice masses evolve, travel, and eventually break apart.
The team does not expect this to be the last major change at Petermann Glacier. Two additional sections, each about 94 and 84 square kilometers respectively, are expected to detach in the future. If both break away, the combined loss from these three calving events would remove approximately 254 square kilometers from the glacier—roughly 22 percent of its floating ice tongue.