A new iceberg has spent part of the Southern Hemisphere’s 2024-2025 summer ricocheting off parts of the Antarctic coastline. Over the past month, the potato-shaped berg has drifted about 250 kilometers (150 miles) from its point of origin near the George VI Ice Shelf’s southern end along the base of the Antarctic Peninsula.

The iceberg’s journey is visible in this animation, composed of satellite images acquired between January 15 and February 15, 2025. The images are from the MODIS (Moderate Resolution Imaging Spectroradiometer) instruments on NASA’s Terra and Aqua satellites, as well as the VIIRS (Visible Infrared Imaging Radiometer Suite) on the Suomi NPP satellite. Note that images from several days during this period were omitted due to cloud cover.

A rift on the George VI Ice Shelf remnant was evident in late 2024, but the iceberg-to-be was still hemmed in by sea ice at the Ronne Entrance—the bay that abuts the southern end of the ice shelf. (The George VI is an unusual ice shelf in that it has both a northern and southern ice front.) By January 2025, most of the seasonal sea ice had melted, and ocean currents carried the new iceberg away.

“I’m impressed by how fast it has moved in the coastal current,” said Christopher Shuman, a retired glaciologist with the University of Maryland, Baltimore County. “It makes me wonder just what is happening in the water under the ice shelf.”

Named A-84 by the U.S. National Ice Center, the berg measures about 30 kilometers (19 miles) long and 17 kilometers (11 miles) wide. It has an area approaching the size of Chicago, Illinois.

Iceberg calving is a normal occurrence for ice shelves. However, factors such as warming air and water along with decreasing protective sea ice can accelerate calving and lead to collapse, as has happened to several ice shelves along the Antarctic Peninsula.

Observations made by explorers beginning in the early 1940s, and later by remote sensing, show that the George VI has been losing shelf ice. For now, the retreat has been gradual, aided by the stability provided by its unique location, sandwiched between the Antarctic Peninsula and Alexander Island.

NASA Earth Observatory video by Lauren Dauphin, using MODIS data from NASA EOSDIS LANCE and GIBS/Worldview and VIIRS data from NASA EOSDIS LANCE, GIBS/Worldview, and the Suomi National Polar-orbiting Partnership. Story by Kathryn Hansen.