Those living in colder climates are no strangers to the occasional heavy snowfall, but few would be remotely prepared for 16 billion tons of snow dropping down in just a few days. As unthinkable as it sounds, this surplus of snow hit Greenland in March 2022 — all from a single storm.
According to a new study published in Geophysical Research Letters, this extreme snowfall event can be explained by atmospheric rivers — narrow bands in the atmosphere that carry moisture and heat outside of Earth’s tropics. In this case, moisture flowed to cooler high latitudes and fell as solid precipitation at high elevations in Greenland.
The March 2022 storm delivered enough snow to offset the Greenland ice sheet’s annual ice loss by 8 percent, leading researchers to wonder how atmospheric rivers will impact the Arctic in the future.
Delivering Rain and Snow
Atmospheric rivers are often cited as a catalyst for ice loss, as they deliver heat and rainfall from mid-latitudes. However, they sometimes have the opposite effect of replenishing ice sheets by prompting short yet intense bursts of snowfall.
An atmospheric river event recently accelerated ice loss of the Greenland ice sheet (the largest ice mass in the Northern Hemisphere) in summer 2021 with copious amounts of rain, but only months later, in March 2022, another event brought 16 billion tons of snow to Greenland. In the search to uncover the true extent of snowfall during that storm, researchers developed a new perspective on atmospheric rivers.
“Sadly, the Greenland ice sheet won’t be saved by atmospheric rivers,” said study co-author Alun Hubbard, a field glaciologist at the University of Oulu, Finland, and the Arctic University of Tromsø, Norway, in a statement. “But what we see in this new study is that, contrary to prevailing opinions, under the right conditions, atmospheric rivers might not be all bad news.”
Understanding the impact of atmospheric rivers on the Greenland ice sheet will prove to be consequential — if the entire sheet were to melt, sea levels would rise by more than 7 meters (23 feet). Atmospheric rivers are also expected to become more frequent and more intense due to climate change, which could bring more rainfall to northern latitudes.
Read More: The Runoff From California’s Storms Has Been so Intense It’s Visible From Space
Digging Into the Past
Researchers searched for traces of the March 2022 storm in southeastern Greenland, in a region that is around 2,000 meters (6,562 feet) above sea level. Here, temperatures are consistently cold enough to retain snow accumulation on the ground year after year, creating a dense, compacted type of snow from previous seasons called “firn.”
The researchers dug into this portion of snow and extracted a 15-meter-long (about 50 feet) firn core that represented nearly a decade of snow accumulation. By analyzing oxygen isotopes and the density of different layers in the core, the researchers were able to determine the exact amount of snowfall during the March 2022 storm.
According to the results, on March 14, 2022, the Greenland ice sheet received 11.6 billion tons of snow, with an additional 4.5 billion tons falling over the next few days. This amount of snow was enough to delay the onset of summer ice melt by about 11 days.
Double-Edged Effects
As global temperatures climb, it’s likely that the precipitation from atmospheric rivers will increasingly turn to rain, exacerbating Arctic ice loss. For the foreseeable future, though, atmospheric rivers may also continue to temporarily reverse the loss of mass in the Greenland ice sheet by delivering extreme snowfall during colder months.
More research, ultimately, is needed to predict how the positive and negative effects of atmospheric river events will balance out in the coming years.
Read More: Ancient Poppy Seeds And Willow Wood Offer Clues To Ice Sheet’s Last Meltdown
Article Sources
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Jack Knudson is an assistant editor at Discover with a strong interest in environmental science and history. Before joining Discover in 2023, he studied journalism at the Scripps College of Communication at Ohio University and previously interned at Recycling Today magazine.
