Anne Clites, a physical scientist at the Great Lakes Environmental Research Laboratory, predicts the water levels of Lake Michigan and Lake Huron will increase by 10–12 inches this upcoming summer from this past summer.

When cold, dry air sweeps across the lakes, it increases the evaporation rate, which results in more ice cover and lake-effect snow, said John Lenters, the senior scientist at the environmental consulting firm LimnoTech.

Although this temporarily decreases water levels, ice lingers into late winter and early spring, capping further evaporation.

Lenters predicts water-level gains this year because of lingering ice will result in cooler summer waters, leading to a later evaporation period next fall. Extra lake-effect snow also will melt to produce runoff water.

For about 15 years, water levels in the Great Lakes have been consistently below average, sometimes by about a foot.

Fisheries scientists and shippers alike have been worried the lower water levels combined with increasingly high water temperatures will damage aquatic ecosystems and affect trade.

“The fact that (Lakes) Michigan and Huron have been that far below for that period is unusual,” Clites said. “In general, it just doesn’t happen.”

Although the weather has felt chillier than average this winter, the freezing temperatures that could cause water levels to increase used to be fairly typical, National Oceanic and Atmospheric Administration meteorologist Nathan Jeruzal said.

Arctic blasts occur every year, but this year, deep freezes permeated farther South and lasted longer than usual, Jeruzal said.

Lenters said it is adjustment to the mild winters in recent years that is making this one feel all the colder.

He called this winter a “reset to normal,” because abnormal trends of warmer temperatures had fluctuated perceptions.

Lenters likened it to a frog sitting in a pot of hot water, and then suddenly jumping out.

“Climate change has changed people’s expectations of what is normal,” Lenters said. “They think it’s the apocalypse.”

Despite the expected temporary increase in Great Lakes water levels, Clites said many still are worried about the “unusual” trend of depletion.

“If you look back 50 or 60 years, (water levels) go up, they go down, they go up, they go down,” Clites said.