Caseville Breakwall Winter 2021

High Temps Drop Great Lakes Ice Coverage Under 20%, Currently Stands at 16%

March came in like a lamb, and the winter thaw is well underway. While the shallow areas of Saginaw Bay are still ice-covered, the Great Lakes ice coverage is waning fast. The other bays in the northern Great Lakes are still fully frozen, and surrounding areas are also seeing ice-over diminish. From early January until February 1st, the ice cover had increased a miserly three-tenths of a percent to 2.4%. However, the cold snap in early February caused the ice cover toward the normal range.

NOAA imaging is showing the ice coverage dynamically shrinking in the past few days on Lake Huron. Lake Ontario, with its deep 800 foot waters, has the highest ice cover going into March at over 75%,

NOAA reported total coverage of the Great Lakes at about 42% as of February 16th. This level was higher than NOAA’s initial projection of 30% at the beginning of the winter. As of March 6th, NOAA reports that coverage has dropped to 16.1%

Great Lakes Ice Coverage – Daily Report

Great Lakes Current Ice Coverage 2021 – Refresh Your Browser to Update – NOAA

The areas that saw the highest coverages during the winter of 2021 were Green Bay off of Lake Michigan, Saginaw Bay, North Channel, and Georgian Bay off of Lake Huron, Apostle Islands and Thunder Bay in Lake Superior, Lake St. Clair, Western Lake Erie, and the 10,000 islands area of eastern Lake Ontario.

The ice bridge between Minnesota’s North Shore and Isle Royale was still evident, barely.

Estimated Ice Thickness of the Great Lakes

Current Estimates of Maximum Ice Thickness – Refresh Your Browser to Update – NOAA

In mid-January, 2021 the Great Lakes had an average ice coverage of 10-15%. The primary reason for the initial low ice cover in 2021 is that the region experienced temperatures 3 to 8 degrees above normal. This warmer than average winter will likely mean less ice coverage. Estimates by NOAA placed the highest ice coverage at 30%, occurring in late February.

What Does The Lack of Ice Coverage Mean

When the Great Lakes don’t freeze over, there is more evaporation. This puts moisture in the air resulting in more cloudy grey days across the region. If a cold snap does occur accompanied by wind, the chance for heavy, localized lake effect snow may occur. Due to higher than normal lake levels, beach erosion and lakeshore flooding may be more likely.

What is The Long Term Great Lakes Average Ice Coverage Rate

The long-term average for maximum Great Lakes ice coverage is about 53.3%. This record high coverage rate for the Great Lakes was 94.7%, set in 1979. The record low ice coverage in the Great Lakes was 11.9% set in 2002.

Great Lakes Annual Max Ice Coverage 1973-2020

Ice coverage data is from NOAA and updated daily. Great Lakes water level data is reported monthly from the Army Corps of Engineers Detroit District.

Forecast of Future Ice Coverage with Climate Change

One study from 1991 hinted that increased CO2 levels across the Great Lakes region would lower ice coverage. Data from 30 years was extrapolated with varied increases in CO2. The potential environmental and socioeconomic impacts of increased CO2 warming include year-round navigation, change in abundance of some fish species in the Great Lakes, discontinuation or reduction of winter recreational activities, and an increase in winter lake evaporation.

Current Great Lakes Water Level Report

The report below is interactive and you can control the display. Click on the image to access the dashboard in a new tab.

Great Lakes Dashboard – Courtesy GLERL

The Detroit Army Corps of Engineers has kept records of Great Lakes ice coverage going back to 1973. The map shows the extent of the maximum ice cover on the Great Lakes for each year. Data is from the U.S. National Ice Center and the Canadian Ice Service. Satellite data is combined with other sources to translate daily ice charts into a percent cover pixel grid.

It is sporadic for all the Great Lakes to freeze over entirely. Yet they experience substantial ice coverage, with large sections of each lake freezing over in the coldest months. During the winter of 2013-2014, frigid temperatures covered the Great Lakes and the surrounding states. The persistent cold caused 91 percent of the Great Lakes to be frozen by early March 2014. This resulted in late winter of freezing temperatures but sunny clear days and nights.

Impact on 2021 Great Lakes water Levels Likely

Great Lakes Water Levels

Ice cover will lessen the impact of evaporation of Great Lakes due to less exposure to the air. It also could lower the amount of lake effect snowfall in the region. Cold temperatures in early January will be a strong indicator if the Great Lakes will approach total ice coverage in the spring of 2020. A high rate of ice coverage will likely mean higher record-setting Great Lakes water levels in the summer of 2020.

Ice Tsunami Destroys Homes Along Great Lakes Shoreline

This shows the power of water and ice when a little wind gets behind an ice flow near shore.

In the winter of 2018, there were two deaths and one rescue on the Saginaw Bay ice in the Upper Thumb in early February. We found a short video that describes the steps to survive falling through ice even if you can’t get yourself out of the water. It’s a fight for survival. How to Survive Falling Through the Ice

Great Lakes winters can be brutal. Getting your car ready for winter is critical. NOAA predicts colder-than-average and wetter-than-average conditions are most likely in the Great Lakes and parts of the Mid-Atlantic and Northeast. The recent cold snap in 2021 means more snow and ice for the rest of the winter. Four Ways to Get Your Car Ready for Winter

Five years ago, the entire Great Lakes was witness to low water levels not seen since 1964. Marina’s were dredging; boats were being damaged on shallow reefs not seen a generation, and lake shipping was facing hard times. There was serious concern about how far it would go and what would happen next. A Look Back – 2012 Marina’s Scramble as Water Levels Dropped

The November 2019 update from the Army Corps of Engineers Detroit District point to an outlook that could mean the Great Lakes will continue to rise and break records in 2020. 2020 Great Lakes Water Levels Look to Break Records

Updated each month from the Army Corps of Engineers’ Excepts – Detroit District’s Monthly and Weekly reports for Great Lakes Water Levels and Great Lakes Water Level History. 2021 Great Lakes Current And Historical Water Levels

Michael Hardy

Mike Hardy is the owner of Thumbwind Publications LLC. It started in 2009 as a fun-loving site covering Michigan's Upper Thumb. Since then, he has authored a vast range of content and established a loyal base of 60,000 visitors per month.

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