Manhattan-sized Arctic ice island that researchers had watched develop for years. Image Credit: Adam Garbo A huge slab of floating ice has broken away from Greenland’s Petermann Glacier, creating an ice island roughly the size of Manhattan. The 76.4 sq km section separated from the glacier’s floating ice tongue on 4 August 2026, marking Petermann’s largest floating-ice loss since 2012. The European Space Agency (ESA) says the newly formed tabular iceberg may be up to 150 metres thick, making it an imposing piece of ice even by Arctic standards. 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. The event is also significant because it is described as the biggest Arctic calving event since 2020. For scientists, the newly independent ice island offers a rare opportunity to watch how a large Arctic iceberg moves, breaks apart and changes slowly over time.
Iceberg breaking away from Petermann Glacier
The break occurred on 4 August 2026, when the large section separated from Petermann Glacier’s floating ice tongue in northwest Greenland. Research involving the University of Ottawa and other institutions, says scientists had been monitoring the area for years. Satellite observations dating back to 2019 showed that fractures had been expanding across the floating ice tongue, along with other signs that the structure was becoming increasingly unstable. The final stages of the separation were captured by satellites operated as part of Europe’s Copernicus programme. Images from the Sentinel-1 mission showed clear weakening along the centreline of the ice tongue on 3 August. By 20:00 UTC on 4 August, the enormous section had separated from the glacier’s eastern side. The event was therefore not completely unexpected. Scientists had watched the cracks develop over several years and had anticipated that a major break could eventually occur.
Sentinel-1 interferometry highlights fractures of Petermann ice tongue. Image Credit: ESA
Size of this new iceberg
The newly separated ice mass covers about 76.4 square kilometres, an area comparable to Manhattan Island. According to the ESA, the iceberg is a flat-topped or tabular piece of floating ice and could be as much as 150 metres thick. Its size makes the event unusual in the Arctic. Large, flat icebergs are more commonly associated with Antarctica, while similarly large ice islands are much rarer in the northern polar region. The scale of the break is also important for Petermann Glacier itself. The ESA reports that the August event represents the glacier’s largest loss of floating ice since 2012 and the most significant calving event recorded in the Arctic since 2020. For researchers, however, the story is not simply about a giant piece of ice disappearing. The newly formed ice island can now be followed as it moves through Arctic waters and gradually changes shape.
Manhattan-sized iceberg. Image Credit: ESA
How did satellites reveal the cracks before the break
Satellite technology gave researchers a detailed view of the changes taking place inside the floating ice. The ESA explains that Sentinel-1 radar observations were used to create an interferogram, which reveals movement and deformation in the ice. The imagery showed fractures that had already developed by April 2026, almost four months before the eventual calving event. The observations were particularly detailed because Sentinel-1C and the newly launched Sentinel-1D satellite were operating together during Sentinel-1D’s commissioning phase. Their one-day repeat observations allowed researchers to measure how fractures spread across the ice tongue and how the surface moved in response to ocean tides.This meant scientists could see that the ice was not simply sitting still. The floating tongue was deforming and responding to forces from the surrounding environment, while cracks continued to develop. Such satellite observations are valuable because Petermann Glacier is remote and difficult to monitor directly. From space, researchers can observe large areas of ice without needing to be physically present on the glacier.\
Possibility of new icebergs breaking away
The latest calving may not be the end of the story. According to SciTechDaily, researchers expect two additional major ice islands could separate from Petermann Glacier if the existing rifts continue to extend across the floating tongue. Those potential ice islands are estimated to cover about 94 and 84 square kilometres. If both events occur, the three ice islands together would remove roughly 254 square kilometres from the Petermann ice tongue. That would represent about 22% of the floating tongue, making the potential future losses considerably larger than the August event alone. The researchers will continue watching the area to see how those fractures develop and whether the expected breaks occur.
Why will scientists keep tracking the new iceberg
The newly formed ice island is more than a dramatic sight from space. Its journey could provide researchers with useful information about how large Arctic icebergs behave after they separate from a glacier. Researchers plan to continue monitoring the aftermath using satellite images, aerial observations and tracking data. Following the iceberg can help scientists understand the processes involved in calving and retreat across Arctic floating ice. There is also a practical reason for keeping a close watch on it. Environment and Climate Change(Canada) is tracking the ice island because large pieces of floating ice can create hazards for ships and offshore operations.As the island drifts and gradually breaks into smaller pieces, those fragments can become more difficult to detect and track. For now, the Manhattan-sized ice island has become a striking new feature of the Arctic. Its separation marks a major change at Petermann Glacier, but it also gives scientists an opportunity to observe what happens next.