On August 4, 2026, Sentinel-1 satellite data recorded the breakaway of a 76‑square‑kilometre segment from the floating ice tongue of Petermann Glacier in northwest Greenland, marking the biggest loss of floating ice since 2012. Sentinel-1 uses radar to observe the Arctic day and night, penetrating cloud cover and enabling continuous monitoring of remote glaciers. An international research team, including scholars from the University of Ottawa, the Universities of Stirling, Lancaster and Leeds, and the Canadian Ice Service, has tracked Petermann Glacier since 2019. In April 2026, interferometric observations revealed deformation and fractures within the ice tongue, indicating progressive weakening. By August 3, Sentinel-1 radar images showed pronounced deterioration along the centreline, and on August 4 the ice segment detached from the eastern edge of the glacier. The resulting tabular iceberg, estimated to be up to 150 metres thick, covers an area comparable to Manhattan. Adam Garbo, a PhD candidate at the University of Ottawa, said the event highlights the rapid changes possible in this system. Anna Crawford of the University of Stirling noted that, although tabular icebergs are common in Antarctic waters, Arctic ice islands are far less frequent. The research team expects two additional ice islands, with areas of about 97 and 87 square kilometres, to calve as rifts continue to propagate. Processed Sentinel-1 data by Molly Hammond, a PhD student at the University of Leeds, enabled precise measurement of fracture propagation and ice motion relative to tidal cycles, illustrating the utility of one‑day repeat synthetic aperture radar observations. Martin Wearing of ESA described the calving as a rare Arctic opportunity to study the dynamics of large tabular icebergs, emphasizing that systematic satellite observations are essential for understanding calving processes and their broader impacts on sea‑level rise and polar ecosystems. Environment and Climate Change Canada is monitoring the iceberg’s trajectory to assess potential risks to shipping routes and offshore infrastructure, as the mass may persist for years before fragmenting into smaller, harder‑to‑detect pieces. Ongoing observations from satellites, aerial surveys and tracking data will continue to document the iceberg’s movement and eventual disintegration, providing further insight into Arctic ice dynamics and associated environmental implications.