The Great Lakes have been slow to freeze this year, compared to years past. Currently, around 2.4% of the Great Lakes are covered by ice, concentrated in the Green Bay region off Lake Michigan and Saginaw Bay in Lake Huron. That's lower than 11% cover at this time last year.
Jia Wang is an ice climatologist for NOAA. He says it's been a warm winter in the Great Lakes region.
"[Ice cover] is very very low, unusually low this year, compared to other years and compared to the average. This year, air temperatures are so warm. Air temperature has a negative correlation with ice cover. Of course, if it's warmer, there's less ice cover," he says.
The average maximum ice cover for the Great Lakes as a whole is 53%, according to Wang. The projected maximum for this year is 30%, with the peak ice cover happening sometime in February or early March.
Richard Rood is a professor of climate science at the Univeristy of Michigan. He says this year is not a one-off event.
"I think it is a part of a trend of the systematic decline of ice that is associated with general wintertime warming that we’re seeing in our region." He adds that it's likely this trend will continue, saying, "The evidence we have right now as well as the evidence and guidance we have from the projections is that we would expect to see continued decrease in ice. The ice season will get shorter. We do not see anything that would divert us from that general trend."
Rood says this warming trend has been occurring for decades, interspersed with the odd cold year, one that might bring a polar vortex.
The impacts of ice cover on the region go beyond the winter, however. Low ice cover now could impact infrastructure, as ice protects shoreline communities from storm damage. Wang and Rood both make reference to Great Lakes species of fish, like the burbot, that rely on ice cover for their spawning cycles, or certain species of trout, that lay their eggs near the shore and rely on ice cover to protect their eggs from damage as species being impacted by lower ice cover.
Rood says that's not to mention historically high lake levels, which are impacted by ice cover and winter precipitation, and winter recreation activities, like ice fishing and winter sports.
"People are going to have to adapt to it. It's not like it's just going to happen this year, and then next year everything is going to be back to normal," Rood says.
