Manhattan-sized ice island breaks off Greenland’s Petermann Glacier

Satellite Monitoring Captures Major Calving at Petermann Glacier

An international team of researchers, led in part by the University of Ottawa, has documented a major calving event at Petermann Glacier in northwest Greenland. The newly separated tabular iceberg broke away from Petermann Glacier’s floating ice tongue on August 4, 2026. The tabular iceberg separated from the glacier’s floating ice tongue and may be as much as 150 meters thick, or close to 500 feet thick. Its surface area is roughly comparable to Manhattan Island, or 29 square miles, giving researchers a rare opportunity to observe how enormous Arctic ice masses develop, move through the ocean and eventually fragment. Petermann Glacier connects the Greenland ice sheet to the Arctic Ocean.

The event was identified by Adam Garbo, a PhD student in glaciology at uOttawa’s Department of Geography, Environment and Geomatics. 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. Researchers had been watching the glacier for years as cracks widened across its floating tongue, and satellite observations captured the final stages of the break. Sentinel-1 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 from the eastern side of the glacier.

Because Sentinel-1 carries a radar, it can observe day and night and through cloud cover, making it particularly well-suited to monitoring remote Arctic glaciers. Using radar imagery from the Sentinel-1 mission, an international team of researchers—partially funded through ESA’s FutureEO ARCTEX project—has been monitoring Petermann. We’ve anticipated this break for years, and seeing it finally happen is remarkable, Adam Garbo, a doctoral student at the University of Ottawa, said in a statement.

Rarity of Arctic Ice Islands Provides New Research Window

Petermann Glacier has shed a rare, Manhattan-sized Arctic ice island that researchers had watched develop for years. The event marks the glacier’s largest loss of floating ice since 2012 and the most significant calving event in the Arctic since 2020—revealing once again how rapidly Earth’s polar landscapes can change. The newly formed tabular iceberg covers an area about the same size of Manhattan and is estimated to be up to 150 meters thick.

Dr Anna Crawford of the University of Stirling said that the newly formed tabular iceberg, estimated to be up to 150 metres thick, presents a rare opportunity to study how large Arctic ice masses form, drift and break apart over time, according to researchers. Satellite imagery from Europe’s Copernicus Sentinel-1 mission shows a 29-square-mile section of Petermann Glacier’s floating ice tongue separating from the glacier in northwest Greenland on August 4, 2026.

Two More Major Calving Events Anticipated

A massive iceberg has broken off from Petermann Glacier—and researchers are anticipating at least two more calving events from Greenland’s Petermann Glacier in the near future. The group, which includes Stirling’s Dr Anna Crawford, warn that two even larger ice islands are expected to break away in the near future. Researchers say two more major calving events are likely.