Giant Iceberg Survives Collision with Joe Island in Greenland

A massive iceberg, spanning over 76 square kilometers, broke off Greenland's Petermann Glacier in August 2026. This event marked the largest glacier calving in the Arctic since 2020. The iceberg later collided with Joe Island but remained intact. Satellites are currently tracking its movement through the Nares Strait.

Iceberg calving is a natural process for outlet glaciers. Scientists monitor these events for insights into long-term glacial stability. Petermann Glacier is one of Greenland's largest marine-terminating glaciers. Its stability influences the flow of ice from the Greenland Ice Sheet into the ocean, which has implications for sea level rise.

The calving event was first identified on August 4 by Adam Garbo, a glaciology doctoral student at the University of Ottawa. He used imagery from the European Space Agency's Sentinel-1 mission. The flat-topped iceberg, known as an "ice island," measured just over 76 square kilometers when it separated. This makes it the largest iceberg from Petermann Glacier since a 2012 event that produced an ice island covering 130 square kilometers.

Scientists had anticipated a larger break from a different rift. The glacier fractured along an unexpected crack, creating a smaller ice island than predicted. Two large rifts remain, expected to release new ice islands of approximately 94 and 84 square kilometers in the future. Glaciologist Mauri Pelto of Nichols College has also tracked the iceberg using National Aeronautics and Space Administration (NASA) and United States Geological Survey (USGS) Landsat satellites.

The iceberg moved down Petermann Fjord at about three kilometers per day. It then encountered Joe Island, a small rocky outcrop at the fjord's entrance. The Operational Land Imager (OLI) aboard Landsat 9 captured the collision on August 23 and 24. Despite its fragility compared to other icebergs, this ice island survived the impact without breaking apart.

Winds and surface currents carried the iceberg out of Petermann Fjord. Satellite observations show it pivoting away from Joe Island and moving southwest through Nares Strait. Over time, tides, winds, ocean currents, and melting will weaken the iceberg, causing it to fracture into smaller pieces. These fragments can travel long distances, posing hazards to shipping and releasing freshwater into Arctic waters.