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Great Lakes’ warming has wintertime domino effect

Coast Guard issues gale watch for Lake Michigan
Posted at 8:32 AM, Nov 29, 2021

CHICAGO (AP) — Winter is just around the corner, but experts say the Great Lakes haven’t gotten the message.

After summer and fall evenings that failed to cool sufficiently, surface temperatures in the massive bodies of water are trending above average, the Chicago Tribune reported.

It's an example of climate change.

“What was kind of jarring was the consistency of the warmer-than-normal conditions,” state climatologist Trent Ford said. “And the lack of cool nights.”

Blame states boasting Great Lakes shorelines.

Minnesota and Wisconsin recorded their third-hottest Junes in history. New York had one of its hottest summers. Lake Huron set a record when it reached nearly 74 F (22 C) in late August.

Illinois brought the heat, too. The state's minimum average temperature for July through October was the highest ever next to 2016, according to National Oceanic and Atmospheric Administration records dating to 1895. The average October temperature set a record at 8 degrees above average.

The disruption in expected seasonal temperatures produces a domino effect.

A hard frost was delayed until the last week of October, Ford said. Allergy season seemed longer. Bugs had an extended biting season. Ford was picking backyard tomatoes far into October.

It continues throughout the calendar. Illinois' most pronounced warming has occurred in winter — minimum temperatures have warmed by more than 3 degrees.

That stretches out warmer water temperatures, which can produce more lake effect snow, according to Ford. Snow slows with the arrival of ice, which itself is delayed by warmer water.

Ice can diminish the damage of coastal erosion. And warmer water, even at depths found in the Great Lakes, pose challenges by welcoming invasive species and generating harmful algae blooms.