Great Lakes Ice Coverage is Shrinking

Great Lakes ice coverage is becoming less reliable and is trending lower over time, with consequences to an important natural ecosystem and the cultural practices based around it.
Recurring 10 p.m. news recording
Published: Feb. 18, 2021 at 9:30 PM CST
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MADISON, Wis. (WMTV) -Our recent stretch of cold weather has been rapidly growing ice on the Great Lakes. Despite the recent cold stretch, a mild first half of winter has ice cover running below average on most of the Great Lakes. While there is significant year-to-year variability in ice coverage, trends show that annual maximum ice coverage on each of the Great Lakes has declined over time. Across all the Great Lakes, the annual maximum ice cover is, on average, 22% lower than it was a half-century ago. Furthermore, ice coverage is becoming less reliable, with more frequent years of extremely low ice coverage. The decline in lake ice coverage is driven by warming air and water temperatures due to climate change. The lake ice season is also contracting in many cases, with lakes now tending to freeze over later and thaw out sooner. While ice coverage has grown this week in excess of 40% on the Great Lakes, it’s still less than the 53% average from 1973-2020.

Our stretch of arctic air is rapidly building ice across the Great Lakes. Total coverage now up to 40.1 percent. That's more than double where we were this time last year!

Posted by Meteorologist Brian Doogs NBC15 on Thursday, February 18, 2021

Winter is the fastest warming season across much of the U.S but particularly in the Northeast and Great Lakes regions, where average winter temperatures have warmed by as much as 5℉ over the past half century. Warming can be difficult for us to perceive during the cold months, especially as it can, seemingly paradoxically, can contribute to more lake effect snow in some areas. Similarly, there are important potential impacts of reduced ice coverage on the lake ecosystem that are easy to overlook, such as lower water levels, warmer waters and increased sunlight penetration, which can in turn influence water quality and challenge the survival of native fish populations.

According to NOAA, the Great Lakes hold 90% of the freshwater in the United States, and 20% of the world’s supply. Not only are they vital sources of drinking water and irrigation for the country as a whole, cultural and recreational practices connected to the lakes and lake ice are deeply rooted in the surrounding communities.

Great Lakes fishing contributed $2.2 billion to the U.S. economy in 2016, representing over 11 million fishing trips. Among these are ice fishing trips—a traditional, cultural practice originating among indigenous communities and popular among modern recreational anglers. In recent years, finding adequate ice cover and thickness has made the activity difficult and highly dangerous. The endurance of other historical and cultural connections with Great Lakes ice, such as ceremonial practices, ice skating and the use of ice roads, is at risk of slipping through our fingers as our climate only continues to warm.


Data on observations of annual maximum ice coverage for each of the Great Lakes was obtained from NOAA’s Great Lakes Environmental Research Laboratory (GLERL).

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