Greenland's Biggest Iceberg Since 2020 Survives Collision With Small Island

A large iceberg calved from Petermann Glacier on Greenland's northwest coast in August 2026, drifted into Nares Strait and collided with a small island along the way, according to NASA's Earth Observatory. Roughly the size of St. Thomas in the U.S. Virgin Islands, it was the largest calving event by any Arctic glacier since 2020.

The calving was spotted on August 4 by Adam Garbo, a doctoral student in glaciology at the University of Ottawa, in imagery from the European Space Agency's Sentinel-1 mission. Garbo and colleagues had been expecting a larger calving once a monitored rift finally cut across the glacier's ice tongue, but the tabular iceberg, or "ice island," instead followed a different fracture, producing a smaller berg than anticipated at just over 76 square kilometers (29 square miles) - still the largest from Petermann since a 130-square-kilometer ice island in 2012, which followed earlier events in 2008 (31 square kilometers) and 2010 (just over 250 square kilometers). As of late August, two large rifts remained, expected to eventually produce ice islands of roughly 94 and 84 square kilometers.

Glaciologist Mauri Pelto of Nichols College tracked the berg using NASA-USGS Landsat 9 satellite images as it drifted down Petermann Fjord at an average of 3 kilometers per day, toward the fjord's junction with Nares Strait. There it rammed into a small rocky outcrop called Joe Island, an encounter captured in Landsat images on August 23 and 24. Collisions with Joe Island, including one that split a 2010 ice island in two, often mark the start of a berg's breakup, but Garbo said the team was "impressed that it survived the interaction without further fragmentation."

The ice island was estimated to be less than 150 meters thick at calving, and Petermann bergs tend to be thinner and more fragile than those from glaciers such as Jakobshavn and Helheim. Wind and currents have since swept it out of the fjord and southwest through Nares Strait, where it will keep fracturing into smaller pieces. Garbo and colleagues noted that ice islands can travel considerable distances, posing hazards to marine activities and infrastructure while distributing freshwater into the ocean as they melt.