A massive iceberg is changing from white to a colorful blue in what scientists say may be its final days, new images from orbit reveal.
Iceberg A-23A, which scientists have been tracking since it first separated fromAntarctica’s Filchner Ice Shelf forty years ago, is currently drifting through the South Atlantic Ocean in a region located between eastern South America and South Georgia Island.
According to experts, the massive hunk of Antarctic ice may soon disintegrate completely, as it continues to lose pieces and drifts steadily toward even warmer waters.
A-23A: A State-Sized Iceberg
At roughly 1,500 square miles when it first broke off in 1986, the A-23A iceberg was almost twice the size of Rhode Island. Over the last four decades, it has dwindled to 456 square miles in diameter. A major impetus for the shrinkage occurred just last year, when large pieces broke off in July, August, and September. With a warm summer in the Southern Hemisphere where the iceberg is located, prospects are unfavorable.
NASA captured a new image of A-23A using the Terra satellite’s MODIS (Moderate Resolution Imaging Spectroradiometer) instrument on December 26, 2025. Despite its reduced size and visible melt pool, the iceberg is still larger than New York City, and remains one of the largest icebergs in the ocean.
A follow-up image taken by an astronaut from the International Space Station only a day later displayed an even greater amount of meltwater on the icebergs’ surface. That meltwater represents the beginning of a cycle that will likely increase the rate at which the iceberg is disintegrating.
Analyzing the Antarctic Iceberg
As the icebergs’ edges melt at the waterline, they create a moat-like rampart that holds the meltwater, visible as a thin white line that surrounds the outer edge of A-23A.
“You have the weight of the water sitting inside cracks in the ice and forcing them open,” explained Ted Scambos, a senior research scientist at the University of Colorado Boulder.
In the image, blue and white streaks are also visible, likely remnants of ice crossing Antarctic bedrock hundreds of years ago, well before it broke off the Filchner Ice Shelf.
“The striations formed parallel to the direction of flow, which ultimately created subtle ridges and valleys on the top of the iceberg that now direct the flow of meltwater,” explained Walt Meier, a senior research scientist at the National Snow & Ice Data Center.
“It’s impressive that these striations still show up after so much time has passed, massive amounts of snow have fallen, and a great deal of melting has occurred from below,” added Chris Shuman, a retired scientist with the University of Maryland, Baltimore County.
Expert analysis of the MODIS imagery suggests A-23A may be experiencing a massive leak, with a lighter region (visible to its left in the images) representing a blowout. It’s suggested that so much meltwater may have pooled on top of the iceberg that its weight allowed it to punch through the surface to the other side.
After the blowout, meltwater may have reached the ocean surface, where it mixed with bits of floating ice surrounding the iceberg. These drastic indicators suggest that the iceberg may have only weeks, or even days, before it completely disintegrates.
“I certainly don’t expect A-23A to last through the austral summer,” said Shuman.
Reaching Summer Waters
The summer brings not only warmer air and water but also clearer skies, exposing the iceberg to more sunlight. In fact, researchers refer to the area where A-23A currently resides as a “graveyard” for icebergs. The chunk of ice has already moved into an area with temperatures slightly above the freezing point and is approaching even warmer waters, which could accelerate the melt.
While the loss of large volumes of Antarctic ice amid climate change is concerning, the iceberg has survived a long journey and has provided scientists with important data over the last four decades. For more than three of those, the iceberg experienced a relatively quiet existence while stuck in the Weddell Sea, before it escaped in 2020.
Once it made its departure, A-23A travelled through an ocean vortex before drifting north and almost reaching South Georgia Island. It briefly became stranded in shallow waters thereafter, before it finally broke free again into the open ocean.
Scientists should soon have more icebergs to study if A-23A breaks up entirely, which includes icebergs A-81, B22A, and D15A, all of which may soon break free from the Antarctic shore and begin their own journeys into the surrounding ocean.
For Shulman, observing A-23A has provided an unprecedented opportunity to study the dynamics of iceberg changes over time.
“I’m incredibly grateful that we’ve had the satellite resources in place that have allowed us to track it and document its evolution so closely,” Shuman said.
“A-23A faces the same fate as other Antarctic bergs, but its path has been remarkably long and eventful,” Shulman added. “It’s hard to believe it won’t be with us much longer.”
Ryan Whalen covers science and technology for The Debrief. He holds an MA in History and a Master of Library and Information Science with a certificate in Data Science. He can be contacted at ryan@thedebrief.org, and follow him on Twitter @mdntwvlf.