A Manhattan-sized iceberg measuring 29 square miles broke off Greenland’s Petermann Glacier on August 4, 2026. Captured by the European Space Agency’s Sentinel-1 mission, the calving event marks the glacier’s largest loss of floating ice since 2012 and the most significant breakup in the Arctic since 2020.
A massive slab of floating ice has detached from one of Greenland’s largest remaining glacier tongues, creating a rare Arctic ice island. The dramatic break at Petermann Glacier in northwest Greenland occurred on August 4, 2026. The newly formed tabular iceberg covers approximately 29 square miles (76 square kilometers)—an area comparable to Manhattan—and is estimated to reach up to 492 feet (150 meters) in thickness.
While large, flat-topped tabular icebergs are common in the Southern Ocean around Antarctica, Arctic ice islands of this scale are far rarer. The event represents the glacier’s largest loss of floating ice in over a decade and stands as the most significant Arctic calving event since 2020.
How Satellite Radar Tracked the Breakup in Real Time
Because Petermann Glacier sits in a remote polar region, researchers rely heavily on spaceborne observation. Europe’s Copernicus Sentinel-1 mission monitored the glacier continuously, utilizing synthetic aperture radar that sees through cloud cover and polar darkness. An international team including researchers from the University of Ottawa, the University of Stirling, Lancaster University, the University of Leeds, and the Canadian Ice Service had been tracking increasing instability along the floating ice tongue since 2019.
Scientists received exceptionally detailed data this year because Sentinel-1C and the newly launched Sentinel-1D operated temporarily in a tandem phase. This arrangement provided one-day repeat observations that allowed researchers to measure surface motion and map how fractures spread across the ice shelf.
“The changes we observed on Petermann Glacier were occurring very rapidly in the lead up to the iceberg calving event, so it was incredibly exciting to monitor the crack propagation with interferometry in near-real time.”
Molly Hammond, a PhD student from the University of Leeds
Interferometric observations acquired as early as April revealed deformation and fractures developing months before the actual separation. Radar imagery captured on August 3 showed pronounced deterioration along the centerline of the ice tongue. By the following day, the vast ice island had detached completely from the glacier’s eastern side.
Historical Context and Prior Calving Events
Petermann Glacier connects the Greenland Ice Sheet to the Arctic Ocean, terminating in a floating tongue that constantly flexes and moves. The glacier has a well-documented history of major calving events, producing large ice islands in 2008, 2010, and 2012. Notable past breaks include a 97-square-mile berg in 2010 and a 50-square-mile berg in 2012.
Despite those historic losses, the floating ice tongue remained relatively stable after 2012, experiencing only smaller-scale fractures until the August 2026 event. Researchers note that while melting floating ice does not directly raise sea levels, the broader loss of ice contributes to a warming climate and accelerates the retreat of glaciers and ice sheets.
“Petermann Glacier has long been one of Greenland’s largest remaining ice tongues. We’ve anticipated this break for years, and seeing it finally happen is remarkable.”
Adam Garbo, a PhD student from the University of Ottawa
Potential for Future Ice Loss at Petermann Glacier
The August calving event may not be the final transformation for the glacier. Existing rifts continue to propagate across the remaining floating ice tongue, leading researchers to project at least two more major calving events in the near future.
Tracking the Newly Formed Ice Island
Breaking away from Greenland marks only the beginning of the ice mass’s journey. Winds and ocean currents will carry the iceberg through Arctic waters, where waves and changing temperatures will gradually reshape it. Over time, large ice islands typically fracture into smaller, harder-to-track pieces.
Because these drifting blocks can persist for years, organizations like the Canadian Ice Service of Environment and Climate Change Canada will monitor the iceberg’s movement alongside researchers using satellite imagery, aerial observations, and tracking data to evaluate potential hazards to vessels and resource operations.
“This type of large tabular iceberg is relatively rare in the Arctic, making this calving event a unique opportunity to study how such a vast ice mass drifts, evolves and eventually breaks apart.”
Martin Wearing, European Space Agency
Researchers will continue to analyze the iceberg's progression to better understand the long-term dynamics of these rare ice masses as they move through the Arctic environment.
