How ice cover on the Great Lakes impacts our weather

WLUK file image.

Nine months out of the year, water washing on shore is the sound you'll hear along the banks of the Great Lakes. But with winter fast approaching, that peaceful sound will disappear as ice takes over.

Jeff Last, meteorologist with the Green Bay National Weather Service office, says there was plenty of ice to go around these last two winters.

"It was very, very cold. We broke quite a few records, streaks of temperatures below freezing or below zero," he said.

That record cold in 2014 ultimately lead to the second highest ice coverage since 1973 on the Great Lakes, with 92.5 percent freezing. And 2015 wasn't too far behind, claiming the fourth spot on that list with 88.8 percent of the lakes frozen during the winter.

That lake ice had a significant impact on our lake-effect snow - or a lack thereof, according to Steven Meyer, a climatologist at the University of Wisconsin-Green Bay.

"The more ice cover you have, the less evaporation you get. And the less evaporation you get, the less lake-effect snow you get," Meyer said.

The ice cover acts like an "off" switch for the lake effect snow process. Meyer says all this ice cover has also boosted lake water levels.

"What really changes the lake levels is the evaporation you get during the winter," he said.

Lake levels have been able to return to normal because of the expansive ice the past two years.

But this winter, a strong El Nino in the eastern Pacific could mean milder temperatures and lower snowfall totals for Northeast Wisconsin.

And this milder weather could buck the recent trends for lake ice.

"We typically would see less ice on the Great Lakes with the milder temperatures. And that certainly will have an impact on our weather here locally and across Great Lake states," Last said.

But in the end we won't know for certain what winter will bring until it's here.

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