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Photo by Deidre Kettunen
According to Steve Ackerman and Jonathan Martin, professors in the UW-Madison department of Atmospheric and Oceanic Sciences, on February 12, the average ice concentration on Lake Superior was 23 percent. That’s not a lot, but it’s a lot more than it was before the big ten-day Polar Vortex.
The National Oceanic and Atmospheric Administration (NOAA) reports that 32 percent of the Great Lakes are now covered by ice. Lake Erie has 73.6 percent coverage, while Lake Ontario has only 11.6 percent coverage. Lake Michigan was at 27.9 percent and Lake Huron at 37.9 percent as of February 12.
Ackerman and Martin said that the 32 percent maximum ice coverage for the Great Lakes is much lower than the average maximum coverage of 53 percent. However, the 2021 coverage is higher than the 2017 and 2020 maximums, which were both at about 19.5 percent.
In 2018, the maximum was 70 percent and in 2019, it was 81 percent.
On average, the maximum ice coverage for the Great Lakes is 22 percent lower than it was a half-century ago.
The recent long cold spell of arctic air has significantly contributed to the ice covering the Great Lakes. Up until this cold snap, the Great Lakes were experiencing a mild winter.
The Canadian Ice Service began in 1973. In 1989, the U.S. National Ice Center used images from the Canadian Ice Service to produce Great Lakes ice cover charts from U.S. and Canadian satellite imagery.
NOAS’ Great Lakes Environmental Research Laboratory has studied the relationship between ice cover, lake thermal structure, and regional climate for more than 30 years. By observing long-term changes in ice cover as a result of global warming, as well as studying lake water levels, water movement patterns, climate patterns, water temperature, and spring plankton bloom, NOAA-GLERL has come up with models to predict the long-term changes in ice cover. Hydropower generation companies, commercial shipping companies and the fish industry use that information.
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