Summer’s coming.

But that’s not distracting a major U.S.-Canada advisory board from trying to learn more about what’s happening beneath Great Lakes ice during the winter.

The topic was the subject of an hourlong webinar hosted Thursday by the International Joint Commission’s Great Lakes science advisory board.

Some 153 people attended.

The IJC is a State Department-level commission that has been advising the United States and Canada governments on mutual environmental issues affecting their shared boundary since 1909, including but not limited to the Great Lakes.

Winter has long been a weak spot of Great Lakes research, in large part because it’s more difficult to gather samples then.

Wicked wind, snow, sleet, and freezing temperatures make it dangerous for research vessels to get out on the water before it ices over.

Mike McKay, a former Bowling Green State University researcher now serving as executive director of the University of Windsor’s Great Lakes Institute for Environmental Research, has at times worked with Canadian and U.S. Coast Guards to get some water samples collected.

But the overall effort has been spotty and largely anecdotal.

What scientists do know is that each of the five Great Lakes are dynamic and change according to the season for anything from light penetration to growth of tiny species known as phytoplankton, one of the building blocks of the food chain for fish.

In past interviews, Mr. McKay has said he was surprised to see how brown portions of the Great Lakes looked during the middle of winter. Tests showed that is a time of year when good, healthy species of algae known as diatoms grow strong.

What worries the IJC and its Great Lakes science advisory board, though, is that scientists are chasing a moving target.

With climate change greatly reducing the amount of ice cover compared to decades ago, and wintertime rain becoming more common, there are a lot of unknowns about how fish species, aquatic plants, water quality, and other factors are changing.

The most dominant species of harmful algal blooms, microcystis, has proven to be more resilient than previously thought and proliferate in areas such as western Lake Erie and Saginaw Bay earlier than before.

HABs are a phrase used to describe toxin-producing algae that can harm people, wildlife, and pets.

Of the hundreds of types of algae, many — such as diatoms — are healthy and contribute to the food chain. HABs, or blue-green algae, are biologically known as cyanobacteria. And one thing that scientists have learned is that the bacteria count varies based on season and location.

“Ice coverage is variable and highly vulnerable to weather patterns,” Heather Stirratt, IJC Great Lakes regional office director, said as she was introducing the panelists. “What this means is that we’re losing winter on the Great Lakes and doing so before we fully understand it.”

Learning more about what happens to each of the five Great Lakes during the winter is an even bigger priority now because of how they appear to be experiencing so much change during that season, compared to the other three.

“Imagine working on a puzzle, but a quarter of the pieces are missing,” Ms. Stirratt said.

Panelists were Maggie Xenopoulos, a biology professor and freshwater ecosystem research chair at Trent University in Peterborough, Ont., and Michael Twiss, a biologist professor at Algoma University in Sault Ste. Marie, Ont.

Ms. Xenopoulos said she and other scientists are looking into socioeconomic and cultural impacts of milder winters on Great Lakes residents, as well as the physical changes to the lakes and their fish communities.

“Changes to winter conditions on the Great Lakes are expected to be wide-reaching,” she said.

While it is difficult to predict all impacts, some of the more obvious ones are likely to be more lake-effect snow, more storms, more flooding, and more coastal erosion. The latter especially can put more algae-forming nutrients into the lakes as more nutrient-rich soil flows into them, Ms. Xenopoulos said.

She also noted that Lake Superior is the world’s fastest-warming lake. It now grows patches of algae some summers, something that was once unfathomable.

“Algae there might be tied to warmer winters,” Ms. Xenopoulos said.

Mr. Twiss echoed the challenge of data-collection during the winter.

“Getting out on the water during the winter is hard to do safely,” he said. “But we need more sampling.”

Newer technologies, such as drones and underwater vehicles, could better assist researchers year-round, Mr. Twiss said.

One of the problems with trying to have scientists become bigger risk-takers during the winter is the lack of rescue operations, he said.

“There’s a whole other aspect we have to consider and that’s the capacity for rescue,” Mr. Twiss said.

Three years ago, on Feb. 9, 2022, several dozen Great Lakes scientists and graduate students fanned out across frozen Great Lakes for what was the first coordinated, regionwide “winter grab” of water samples beneath ice.

Even that one was a little risky.

The closest such grab near Toledo was from Lake Erie’s Sandusky Bay. It was done by Mr. McKay and his longtime colleague, Bowling Green State University algae researcher George Bullerjahn, as well as a BGSU graduate student at the time, Ryan Wagner.

Early February was chosen because that is when peak ice normally forms. But the ice on Sandusky Bay was so thin that year that the sample was taken from a shallow, nearshore part of the bay because of safety concerns.

There was a subsequent winter grab this past February and another one is planned for 2026, Mr. Twiss said.

Many of the Great Lakes science advisory board’s findings are in a new IJC report.

“The science advisory board report, we hope, raises the profile of winter Great Lakes science,” Mr. Twiss said. “We felt, as researchers, there was a need for this research and we’re running out of time.”

He and Ms. Xenopoulos were asked how cutbacks in federal funding could exacerbate the problem. Neither had a remedy, other than making the public more aware of the need for more wintertime sampling.

“Winter science efforts can benefit from better public awareness,” Mr. Twiss said.

First Published May 17, 2025, 5:00 p.m.