Satellite picture of Iceberg A-23A recorded on November 28, 2023, by the Moderate Resolution Imaging Spectroradiometer on NASAs Terra satellite.
Stuck on the seafloor for decades, Iceberg A-23A now freely wanders northward toward warmer, iceberg-destroying waters.
For years, Iceberg A-23A sat quietly, out of sight, off the coast of Antarctica. The berg has actually been attracting notice in November 2023 as it wanders northward throughout the Weddell Sea– closer to shipping lanes, islands populated by wildlife, and warmer iceberg-destroying waters of the Southern Ocean.
On November 28, 2023, the MODIS (Moderate Resolution Imaging Spectroradiometer) on NASAs Terra satellite acquired this image of the iceberg, 37 years after it broke from the Filchner Ice Shelf (east of the bigger Ronne Ice Shelf). On this day, the berg drifted near several islands at the idea of the Antarctic Peninsula, about 1,700 kilometers (1,000 miles) from its birth place.
As of November 24, 2023, the iceberg measured about 4,300 square kilometers (1,700 square miles), according to the U.S. National Ice. Icebergs A-68 and A-76 briefly took the largest iceberg title in 2017 and 2021, respectively, before they fractured.
NASA Earth Observatory images by Wanmei Liang, using MODIS information from NASA EOSDIS LANCE and GIBS/Worldview and data from the Antarctic Iceberg Tracking Database.
Because then, it has invested the warmer months of the year riding the Weddell Sea Gyre, an ocean current that spins clockwise and pushes icebergs in the western Weddell Sea to the north.
Since November 24, 2023, the iceberg determined about 4,300 square kilometers (1,700 square miles), according to the U.S. National Ice Center. That makes it the largest of any iceberg presently adrift in the worlds oceans. Larger bergs have come and gone. Icebergs A-68 and A-76 briefly took the largest iceberg title in 2017 and 2021, respectively, before they fractured.
Past icebergs in this location, such as A-68A and A-76A, ultimately left the clockwise flow of the vortex and got in the Drake Passage– a turbulent body of water in between South Americas Cape Horn and Antarcticas South Shetland Islands. From there, they typically move north toward the South Atlantic and quickly melt in the areas warmer waters.
NASA Earth Observatory images by Wanmei Liang, utilizing MODIS data from NASA EOSDIS LANCE and GIBS/Worldview and information from the Antarctic Iceberg Tracking Database. Worldview animation by Karin Kirk, NASA/JPL-Caltech using MODIS imagery from NASAs Aqua and Terra satellites. Story by Kathryn Hansen with image analysis by Christopher Shuman, NASA/UMBC.
The iceberg broke from the Filchner shelf in 1986 and quickly ended up being stuck on the seafloor of the southern Weddell Sea. The icebergs path, charted in information readily available from the U.S. National Ice Center since 2011, is visible in the map above.
The berg became unstuck from the seafloor in the early 2020s, likely due to melting from below the waterline. By March 2023 it drifted freely along with other substantial bergs. Ever since, it has actually spent the warmer months of the year riding the Weddell Sea Gyre, an ocean existing that spins clockwise and pushes icebergs in the western Weddell Sea to the north.