NASA shows iceberg A-23A turns Blue: One of Antarctica’s oldest giants (Image source – NASA)
Iceberg A-23A first broke away from Antarctica in 1986. That was nearly forty years ago. Now the iceberg is far from where it began, floating in the South Atlantic, darker in places, soaked through with blue meltwater, and visibly coming apart.When it calved from the Filchner Ice Shelf in 1986, A-23A was immense. Almost twice the size of Rhode Island, it stretched across roughly 4,000 square kilometres. What remains today is much smaller. Estimates from early January 2026 suggest an area of about 1,182 square kilometres, after several large fragments broke away during the latter half of 2025 as the iceberg entered warmer seasonal conditions.
A giant iceberg that drifted away from Antarctica in 1986
Satellite images taken in late December show what the iceberg looks like now. Pools of blue water sit across its surface, collected in shallow depressions and long grooves. Even after decades of thinning and breakage, the berg is still larger than New York City. A photograph taken a day later from the International Space Station shows the water spread even more widely, the surface looking soft, uneven, and heavy.
Why blue meltwater is spreading across the iceberg
Some of the blue areas appear almost mushy. Scientists say this kind of surface often develops when meltwater gathers inside cracks and slowly forces them wider. The water is not just sitting on the ice, but pressing into it. Along the outer edge, a thin white rim circles parts of the berg, holding water back. This pattern, sometimes called a rampart moat, forms as the iceberg’s edges melt and flex upward at the waterline.
A giant iceberg that drifted away from Antarctica in 1986 ( Image Source – NASA)
Ancient markings still shape the iceberg’s surface
The long straight streaks that cut across the surface seem older, less tied to what is happening now. These lines likely date back hundreds of years, from when the ice was still part of a glacier scraping across Antarctic rock. That movement carved shallow ridges and channels into the ice. Even after years at sea, snowfall, and melting from below, those marks still shape how water flows across the surface.It surprises some researchers that the patterns are still visible at all. The iceberg has been through a lot since then. It grounded, fractured, refroze, drifted, and thinned, yet the old structure keeps showing through in subtle ways.
Signs the iceberg may be nearing its end
One area near the edge looks different. Brighter, rougher. It may be what scientists describe as a blowout, where the weight of pooled water becomes too much and forces a sudden path downward. In that case, meltwater could have drained tens of metres to the ocean surface, spilling out alongside loose ice and creating a plume of freshwater.Taken together, these features suggest an iceberg in its final stages. A-23A is now floating in water close to 3 degrees Celsius and moving toward even warmer currents. This part of the ocean has a reputation among ice scientists. Few large bergs last long once they arrive here.
A long and unusual journey from Antarctica
Its journey has already been unusual. After breaking free, A-23A remained grounded in the Weddell Sea for more than thirty years. When it finally moved again in 2020, it spent months spinning slowly in place, caught in an ocean vortex known as a Taylor column. Later, it drifted north, came close to South Georgia island, grounded again, then slipped back into open water, where it has been steadily breaking apart.Some scientists have followed A-23A for most of their careers. Satellite records have made it possible to watch its changes in detail, year after year. Its path has been longer and stranger than most.
Other massive icebergs still waiting near Antarctica
As this iceberg fades, others remain along the Antarctic coastline. Several large ones are still parked near the continent, quiet for now. In time, they will move too, drifting north, changing shape, leaving brief marks on the ocean before disappearing. Go to Source
