Rapid freezing of Great Lakes during record cold snap signals weather impacts for the rest of winter

By Brian Lada, AccuWeather meteorologist and staff writer
February 05, 2019, 11:54:46 AM EST

The recent spell of record cold across the midwestern United States has caused ice on the Great Lakes to reach levels not seen since 2014.

Little ice could be found on the waters of the Great Lakes during the first part of winter as much of December and the first part of January featured warmer-than-normal conditions across the region.

“Ice coverage was actually well below normal the first half of January, so there has been a rapid increase over the past two to three weeks,” AccuWeather Senior Meteorologist Brett Anderson said.

great lakes ice Feb 1

The key factor that caused this sharp increase in ice coverage was the subzero temperatures brought on by the polar vortex.

Lake Erie had the most pronounced rise in ice, spiking from near zero percent in mid-January to over 90 percent by the start of February.

As a result, February started off with more ice on the lake than any other year dating back to 2014, according to historical data from the Great Lakes Environmental Research Laboratory (GLERL). The same could be said for ice coverage on the Great Lakes as a whole.

great lakes ice past 10 years

The far-reaching ice could have implications on the weather around the Great Lakes in the coming months.

In particular, the higher-than-normal amount of ice could lead to less lake-effect snow throughout the rest of the winter.

Lake-effect snow falls when cold Arctic air blows over the comparatively warm waters of the Great Lakes, causing clouds to form which can unload heavy snow downwind of the lakes.

However, when the lake water freezes over, it reduces the frequency and severity of lake-effect snow.

“Interestingly, lake-effect snow can fall when the lake surface is completely covered in ice. This is because a frozen lake is relatively smooth, when compared to the hilly terrain of the land. In this case, it is the effect of friction that causes some lake-effect snow to fall over the land,” AccuWeather Senior Meteorologist Alex Sosnowski explained.


The recent expansion of ice on the Great Lakes is welcomed by the ice fishing industry, which requires thick ice that can support the weight of fishers and their equipment.

“The fishing around Cleveland is mostly in the more protected harbors for a variety of species. There are a number of factors involved, including ice cover being good,” Mike Durkalec, Cleveland Metroparks, fisheries biologist told AccuWeather.

Not only is the ice good for those who go ice fishing, but also for the fish themselves.

Some species of fish benefit from the lower water temperatures, including Lake Superior’s lake trout, the Associated Press reported.

great lakes ice satellite on feb 1

The Great Lakes as seen from space on Feb. 1, 2019. (Image/NOAA/MODIS)

As the ice benefits both ice fishers and the fish they seek, it can help to reduce the population of invasive species that now reside in the waters of the Great Lakes.

When ice closer to shore becomes thick enough where it actually reaches the bottom of the lake, it can slow the growth of invasive species that live in the shallower water, such as the zebra mussels, Minnesota Public Radio News reported.

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Although there has been a spike in the amount of ice, most of the new ice is still relatively thin, so it may melt in the coming days as the recent record-setting chill has been replaced by a spell of milder air.

“Shallow Lake Erie is about 90 percent covered with a majority of that being thin ice (2 to 6 inches thick),” Anderson said.

“I do not see much change with this over the next two weeks, if anything maybe a slight decrease in coverage,“ Anderson added.

However, colder and stormy weather is expected to return.

“The pattern will lock again for the second half of February with more cold and stormy weather for the eastern half of the nation,” AccuWeather Expert Long-Range Forecaster Paul Pastelok said.

This flip in the weather pattern will likely result in more ice encasing the Great Lakes and cause the ice already in place to thicken.

The next long-duration chill will coincide with the time of winter when the lakes typically experience their highest ice coverage.

“Maximum ice cover on the lower lakes (like Lake Erie) normally occurs between mid-February and end of February. Maximum ice cover on the upper lakes (like Lake Superior) normally occurs between end of February and early March,” the GLERL said on their website.

The ice that forms on the Great Lakes during the winter can help to dictate the weather across the region heading into the spring and potentially early summer. The more ice, the longer it will influence the region’s weather.

“Ice extent plays a part in determining water temperature in the lakes later in the year, as incoming heat will have to melt the ice before it warms the water below. However, meteorological conditions and heat storage in the lakes are also critical components to the thermal cycle in the lakes," the GLERL said.

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