Manhattan-Sized Iceberg Breaks Away From Greenland's Petermann Glacier

Europe's Copernicus Sentinel-1 mission has captured a major breakup at Petermann Glacier in northwest Greenland, where a 76-square-kilometre section of the glacier's floating ice tongue broke away on August 4, 2026. It is Petermann's largest loss of floating ice since 2012 and the biggest Arctic calving event since 2020. The new tabular iceberg, or "ice island," is the size of Manhattan and may be up to 150 metres thick.

Radar images from Sentinel-1 on August 3 showed deterioration along the centre of the ice tongue; a day later, the ice island had separated from the glacier's eastern side. Its radar can observe day and night through cloud cover. An international team — from the University of Ottawa, the Universities of Stirling, Lancaster and Leeds, and the Canadian Ice Service of Environment and Climate Change Canada — has tracked Petermann with Sentinel-1 since 2019, partly funded by the European Space Agency's (ESA) FutureEO ARCTEX project. Interferometric observations in April had shown deformation and fractures in the ice tongue, months before it broke.

Adam Garbo, a PhD student at the University of Ottawa, said Petermann "has long been one of Greenland's largest remaining ice tongues," and researchers had "anticipated this break for years." Petermann last produced large ice islands in 2008, 2010 and 2012; since then it had stayed comparatively stable apart from smaller calvings. The fracture record was possible using one-day repeat synthetic aperture radar (SAR, a technique that builds sharp ground images from satellites) gathered during the Sentinel-1D satellite's commissioning alongside Sentinel-1C.

Researchers say the break may not be the final major change: two more ice islands, of about 97 and 87 square kilometres, could detach as existing rifts keep spreading. Environment and Climate Change Canada is tracking the iceberg's path and assessing risks to shipping and offshore infrastructure. Ice masses this size can stay in the ocean for years, slowly fragmenting into smaller pieces that grow harder to track.