Surprising Impact of Atmospheric Rivers on the Greenland Ice Sheet
Led by Dr. Hannah Bailey from the Water, Energy, and Environmental Engineering Research Unit, the study provides fresh insights into these transient weather phenomena. While atmospheric rivers are typically associated with delivering heat and moisture from lower latitudes into the Arctic—often intensifying ice loss—the research highlights their previously overlooked role in providing snow mass recharge.
Published in Geophysical Research Letters, the study investigates an atmospheric river event in March 2022 that caused Arctic temperatures to rise more than 20°C above their long-term average. Remarkably, this single event also delivered over 11 billion tons of snow to Greenland, equivalent to nearly half of Finland’s average annual snowfall, in just one day.
Using a 15-meter-long core retrieved from Southeast Greenland – capturing nearly a decade of past snow accumulation – the team discovered a dense, well-defined layer formed by the 2022 atmospheric river. This layer, identified by its unique chemical “fingerprint”, preserves a detailed record of the source, magnitude, and timing of the immense snowfall.
“These samples allowed us to pinpoint the extraordinary snow from this atmospheric river. It’s a rare opportunity to directly link such an event to Greenland’s ice sheet dynamics,” said Dr. Hannah Bailey, Principal Investigator.
The team found that the large snowfall did more than just replenish the snowpack; it also delayed the onset of the summer ice melt season. “The fresh snowfall significantly boosted the ice sheet’s albedo, its ability to reflect sunlight. This reduced the absorption of solar energy, keeping the surface cooler and postponing melt, even in warmer-than-average conditions,” explained Dr. Bailey.
As a result, the team estimated that Greenland’s annual mass loss to the ocean was reduced by approximately 8 % in 2022 due to this single event.
Professor Alun Hubbard, co-author of the study and Director of the Thule Institute, emphasised the significance of these findings: "While the Greenland Ice Sheet won’t be saved by atmospheric rivers, this research challenges the idea that they only worsen ice loss. I’ve been studying the impact of rainfall on Greenland for over a decade, and this study shows that contrary to prevailing wisdom, under the right conditions, atmospheric rivers might not always be bad news for the ice sheet.”
As climate change intensifies, atmospheric rivers are projected to become more frequent and intense, making it critical to understand their complex impacts across the Arctic – including the Nordics, where they have significant implications for flooding and water resource management. This study falls under Bailey’s Research Council of Finland project investigating how ice sheets and glaciers are responding to a warming climate, as winter snowfalls increasingly shift to rain.
Article:
Bailey, H. and Hubbard, A. Snow Mass Recharge of the Greenland Ice Sheet Fueled by Intense Atmospheric River. Geophysical Research Letters (2025).
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