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Great Lakes ice cover plummets to record mid-February low

As of Feb. 15, ice covered only 6 percent of the Great Lakes amid abnormally warm temperatures

George Miller swims in the frigid waters of Lake Michigan on Feb. 2, as he does every morning. In the background is downtown Chicago. (Erin Hooley/AP)
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In the midst of an unusually warm winter across much of the northern United States and southern Canada, the Great Lakes now have the least ice cover on record for the middle of February, which is typically when the ice begins to reach its maximum extent for the season.

As of Feb. 15, ice covered only 6 percent of the Great Lakes, compared with a historical average for the date of 41 percent, according to data from the National Oceanic and Atmospheric Administration’s Great Lakes Environmental Research Laboratory. The previous record low for Feb. 15 was 7.8 percent in 2012.

This winter’s lack of ice — part of a longer-term decline in Great Lakes ice coverage tied to human-caused climate change — could have implications across and downwind of the lakes not just for the rest of this winter and the coming spring and summer, but all the way into next winter.

“There have been significant downward trends in lake ice for many years. This year is a continuation of warming winters and declining ice,” University of Michigan climate researcher Richard Rood said in an email. “The downward trend has been punctuated by some years of high ice coverage, related to cold air outbreaks.”

The lack of ice can have both short- and longer-term effects across and downwind of the Great Lakes. For example, the open waters could fuel heavier rain or snow in the coming weeks.

“Low ice cover can have pretty dramatic effects on local weather patterns, leading to increases in lake-effect precipitation downwind of the lakes,” University of Michigan lake modeler David Cannon said in an email. “In the absence of ice, there is nothing to block evaporation from the surface of the lakes, and increased evaporation means increased rain or snowfall.”

The lack of ice has some benefits, such as a longer shipping season, but also negative impacts including reduced hydropower generation and lost income from ice fishing. The low ice this winter could actually lead to increased ice cover next winter, according to Great Lakes Integrated Sciences and Assessments, a collaboration between the University of Michigan and Michigan State University supported by NOAA.

Of the lakes, Erie has the least amount of ice cover at less than 0.1 percent, compared with a historical average of 70 percent, while Huron has the most ice cover at 10.6 percent. Water temperatures across the Great Lakes are running about 1.5 to 2 degrees above average.

Great Lakes ice coverage can fluctuate significantly from year to year. The highest annual maximum ice coverage was 95 percent in 1979 and the lowest was 12 percent in 2002, with a long-term average of 53 percent. This winter will not set the record for the lowest annual maximum ice extent, as ice cover briefly peaked at 21.2 percent on Feb. 4, before plummeting with warmer temperatures.

The weather has been particularly warm this week, especially across the eastern Great Lakes, where temperatures Wednesday were about 20 to 25 degrees above average. Since the beginning of January, temperatures across the Great Lakes and into the southern portions of Ontario and Quebec have been running around 6 to 12 degrees above average.

The winter has been so warm that the Rideau Canal Skateway in Ottawa, the world’s largest natural ice-skating rink, may not open this season.

Before this winter, the Great Lakes experienced record-low ice cover as recently as January 2021, with coverage dipping to 1.3 percent on Jan. 17, 2021, although it eventually recovered to 45.8 percent on Feb. 19, 2021.

“If you look at the historical record of ice cover in the Great Lakes, you can see a pretty dramatic decrease in both the annual ice cover duration (i.e. total number of days with surface ice) and the ice cover maxima (i.e. maximum annual ice cover),” Cannon said. “There’s some evidence that we’re also seeing increases in the variability of ice cover in recent decades, which can make long-term predictions more difficult.”

Maximum ice coverage typically occurs in middle to late February on the northernmost lakes, and between the end of February and early March on the southernmost lakes.

Rood does not foresee a major increase in ice happening this winter. “Given that it is the middle of February and that, in general, the coldest temperatures are increasingly isolated to January and February, it is my personal opinion that a significant ice season is unlikely,” Rood said. “Even if the ice is produced, it will not likely be enduring into late spring.”

A 2021 study found pronounced warming of Northern Hemisphere lakes in the past 100 to 200 years, with the Great Lakes leading the way in rising water temperatures, decreasing ice cover and shrinking ice seasons.

The Great Lakes are not alone in their lack of ice this winter. Sea ice around Antarctica reached a record low this week. Globally, NOAA recently reported the lowest January sea ice extent on record.