A satellite image of the Great Lakes on February 24, 2024. NASA
On the North American Great Lakes, ice cover usually peaks in late February or early March. But currently, the lakes are nearly ice-free.
Typically in late winter, ice sprawls across more than 40 percent of the lakes, but at present, ice cover stands at just around 4 percent. For the past half-century, ice cover has trended down as winters have grown warmer, declining by a quarter on average since 1973. At the same time, ice season has shortened by nearly a full month.
Ice cover on the Great Lakes from 1973 to 2024. NASA
This year, El Niño fueled an especially warm winter, and in February, ice cover reached its lowest level on record. “We’ve crossed a threshold in which we are at a historic low for ice cover for the Great Lakes as a whole,” said NOAA scientist Bryan Mroczka.
The lack of ice has left shorelines more vulnerable to wind, waves, and flooding, and left spawning fish more exposed to predators. It has also disrupted some winter sports, such as ice fishing.
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