The Great Lakes have seen record low levels of ice cover this winter.
The National Oceanic and Atmospheric Administration says the percentage of the lakes covered with ice was in the single digits for much of February, although it rose to 12% by the 19th.
What does the low ice cover mean for the shoreline? U.S. Army Corps of Engineers coastal engineer Jim Selegean tells us the shoreline is usually protected from erosion in the winter by the ice cover.
“A complex of ice builds out into the lake as the winter goes on and basically it armors the shoreline,” Selegean said. “So, it’s like all the shore protection that we see on the Great Lakes stopping the energy of the waves from hitting the bluffs, which is what we care about because we built our infrastructure on top. Shore ice has the same effect.”
With less ice cover, Selegean says the coast faces a risk of more erosion. He tells us climate forecasts anticipate continued dwindling of ice coverage each winter, so ongoing maintenance along the shoreline to prevent erosion may be needed moving forward.
Selegean adds because of the way sand moves, marinas and harbors may be looking at a need for more frequent dredging in the future.
“For three months out of the year, there’s pretty much no sediment being deposited in our navigation channels on Lake Michigan.
But with less ice, that’s more months of the year when sand moves around.
Selegean doesn’t know if this winter has seen significant coastal erosion because that’s measured by aerial photos that haven’t been analyzed yet. He says another drawback of reduced Great Lakes ice could be related to fish that rely on it for protection.
