Iceberg A23a, which has lost more than half its area in recent decades, could completely disintegrate in the coming days or weeks, NASA scientists warn. Satellite observations indicate large pools of meltwater have formed on the surface of the ice mass, indicating structural weakening.
“These signs indicate that iceberg A23a could completely disintegrate in just a few days or weeks… For scientists who have monitored it their entire careers, this is both a sad and significant moment,” NASA notes.
Iceberg A23a calved from the Filchner Ice Shelf in 1986 with an area of 4170 square kilometers. It has been gradually shrinking in recent decades—by December 2025, it had lost 67% of its original area, giving way to iceberg D15a. A23a is currently drifting in the South Atlantic, southeast of South America.
After more than 30 years a ground, the iceberg began moving again in November 2023. In the spring of 2024, it was moving along the Antarctic Peninsula, heading into the Scotia Sea. The loss of A23a will be a significant event for researchers studying the planet’s largest ice masses.
