Source: AGU Advances
As meltwater drains through and beneath a glacier, it can alter how the ice flows and whether it breaks apart. Meltwater can also cause feedbacks that lead to more ice loss. Understanding when and how glacial meltwater drains is therefore critical to predicting how fast glaciers will lose ice and how that loss will affect sea level.
Chudley et al. modeled how the rate of water flowing into a glacier relates to seasonal changes in the forces that squeeze and stretch ice—forces caused by gravity pulling the glacier downhill, by the ice sliding over subglacial water, and by how portions of the ice interact with the ocean.
The researchers focused on the Sermeq Kujalleq glacier (also known as Store Gletsjer or Store Glacier) in Greenland. In spring, meltwater can fill cracks, or crevasses, that run through the surface of this glacier. These crevasses sometimes go on to drain as the year progresses.
The researchers used satellite imagery from the Sentinel-2 mission to see how much water was present in crevasses between 2016 and 2022, focusing especially on 2019, when the Sentinel-2 satellites provided the best coverage of the glacier. They fed those data into a convolutional neural network to map water cover through the season and looked for a relationship between the mechanical forces acting on the ice and the formation and drainage of crevasse ponds.
The researchers found that the mechanical forces acting on ice are the dominant factor in determining when crevasse meltwater drains into a glacier. When seasonal changes cause ice to stretch, crevasses can drain suddenly, releasing the water they held.
The Greenland Ice Sheet sheds trillions of gallons of water each year, and knowing when to expect that water to drain through the ice sheet is key to understanding processes such as how the glacier slides across the bed and when meltwater emerges in the ocean. The study’s results likely also shed light on dynamic processes in other glaciers and ice sheets, the authors say, and should help inform representations of ice behavior in numerical models. (AGU Advances, https://doi.org/10.1029/2025AV002150, 2026)
—Saima May Sidik (@saimamay.bsky.social), Science Writer
Citation: Sidik, S. M. (2026), Stretching and squeezing release glacial meltwater, Eos, 107, https://doi.org/10.1029/2026EO260152. Published on 26 May 2026.
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