Antarctica's Hidden Kronshtadskiy Lake Lost 20.6 Billion Gallons, Satellites Show
Radar tracking of sinking ice above the East Antarctic lake reveals a drainage that left a 6.4-meter dent and hints at a plumbing network beneath the ice sheet.
A lake buried beneath East Antarctica's ice has left a mark visible from space. By tracking a sinking patch of ice, researchers have estimated that Kronshtadskiy subglacial lake, near the Amery Ice Shelf, lost about 78 million cubic meters of water, or roughly 20.6 billion gallons, between 2016 and 2021.
The study, published in Scientific Reports by Jihyun Moon and Hoonyol Lee of Kangwon National University in South Korea, found that the ice above the lake sank by more than 6 meters (20 feet) at its center as the water drained out. Tracking that motion lets scientists study water they cannot see directly. When a buried lake loses water, the ice overhead can sink. When it refills, the surface can rise.
The water matters because it can reduce friction between ice and bedrock, affecting how readily glaciers slide. But satellite altimeters, which measure surface height, leave gaps between their ground tracks. Radar imaging can map movement over a wider area, though Antarctic ice flows sideways as well as up and down, and both motions affect the signal.
To separate them, the team compared Sentinel-1 radar images taken 24 days apart against a reference period when the lake area looked relatively stable. Subtracting the background motion exposed the sinking surface, a method that works if the glacier's sideways flow stays sufficiently steady.
The analysis revealed a roughly circular depression covering about 61 square kilometers (24 square miles). At its center the reconstructed surface dropped about 6.4 meters (21 feet) over five years, while the average lowering across the affected area was about 1.3 meters (4.3 feet). Multiplying the area by the surface lowering gave the water-loss estimate. The researchers note that the map shows the lake's effect on the surface, not its underground shoreline.
Most of the sinking came early. The center fell about 3.8 meters (12.5 feet) in 2016 and 2017, after which the rate slowed substantially. The depression kept deepening gradually, with little sign of substantial refilling. "This behavior implies either prolonged drainage or repeated partial drainage events, rather than a single catastrophic outburst," the researchers write. Measurements from the CryoSat-2 and ICESat-2 satellites broadly supported a pattern of sinking followed by stabilization, although they differed in the detailed timing and locations they sampled. A 2025 satellite survey had independently identified Kronshtadskiy, and the new work provides a detailed reconstruction of how it drained.
The surrounding ice offered a further clue. Downstream from Kronshtadskiy, one circular feature rose while another farther along sank. That arrangement could reflect water leaving Kronshtadskiy, filling a neighboring lake and draining from another, suggesting a hidden network of connected lakes under the ice. The researchers present this as a possibility that the patterns suggest, not a confirmed path, since the radar data show only how the surface moved.
