It’s a matter of degrees: How warmer lake waters impact recreation and our health

Our region experienced one of the mildest winters on record during the 2023/24 season. Storm Track Meteorologist Brandon Weatherz investigates how our weak ice season will affect our summer fun on the water, and how the warmer waters could affect our health.


What low ice levels and warmer waters mean for our area lakes

While our mild winter was good for some, the lack of snow and ice plays a big impact on the health of our lakes and on our recreation.

A stone’s throw from the Canadian border is an island on a lake that Steve Bergerson has called home for decades.

“I’ve had 49 winters, this’ll be 50 summers,” Bergerson said.

Out here, reliable lake ice isn’t just essential for winter recreation. It’s a bridge connecting Bergerson to the town where he’s a pastor.

“The ice just hasn’t been safe,” Bergerson said, “We’re used to three months out of the year taking our vehicles across, and otherwise snowmobile. This year, because we had no snow, we couldn’t really use the snowmobile.”

Usually, a lack of snow would allow for strong ice, but this year was so warm that the ice wasn’t thick enough to lock into place.

“That ice was just shifting and moving and pushing up dirt, and some of the docks here look like Jenga games gone bad, and these cabin owners are gonna come up, and they’re gonna be in a world of hurt,” Bergerson said.

Every ice-in and ice-out brings a stretch of time where Bergerson can’t be on the island. He said, “People let us stay at their places, unoccupied cabins and things like that on the road.”

RELATED STORY: Bear Island inaccessible due to lack of ice

And this year, the amount of time spent with unsafe ice was at a peak.

“That was our third weekend that we had spent on main land,” Bergerson said, “That’s as much as I’d ever want to do.”

LOW WATER LEVELS

Another consequence of the winter is low water levels, not just on Crane Lake, but on Vermilion River which feeds it.

“I’ve never seen the river not in the flood plains. This is really low flow. Even looking down the other way of the river, you can see boulders and the rapids, and they should be completely covered. So we’ve got very little coming to refill these lakes,” Bergerson said.

Low lake levels this early could spell trouble going into the summer.

“There are surprise rocks out there that you know nothing about that are just below the surface,” Bergerson said, “It’s a good time to carry a spare propeller.”

RELATED STORIES: Watch additional stories in the Extreme Weather series.

WARMER WATERS

While this year feels extreme, data suggests it’s part of a long-term trend.

Jay Austin, a professor with UMD’s Large Lakes Observatory, said, “The trend over the last 40 or 50 years is towards warmer waters, less ice, and all of the things that are consistent with the idea that the atmosphere is getting warmer.”

Austin studies how lakes respond to changing seasons with a focus on the Great Lakes. He stresses that we’re still going to have cold and icy winters, but with how sensitive the ice formation process is, it’s subtle differences over a long time that will shift our concept of a normal ice season.

“The difference between a high ice year,” Austin said, “And a year with no ice like this year can be due to differences in average winter air temperature of three or four degrees Fahrenheit.”

Austin said, “If we, climatically, are suddenly just a few degrees warmer, that means that in a typical year, we’re just not going to see ice out on the lake.”

The short-term impacts of this past record-setting winter will be warmer lakes this summer.

“This year, instead of six weeks of warming, we might have ten or twelve, and so we’re going to see significantly higher surface water temperatures across the lake, and probably across the Great Lakes System,” Austin said.

AN INCREASE IN ALGAL BLOOMS

The greatest concern that comes with warm waters is an increase in algal blooms.

Chris Fistrup, a lake and stream scientist with the Natural Resources Research Institute, said, “What I’m anticipating is we’re going to have a big bloom year.”

Fistrup is studying a new hazard that has emerged in the St. Louis River Estuary in recent years.

“So we look out here behind us right now and the waters are, well, they’re a little brown today. If we came back the next day and they were green and looked like pea soup, and maybe there was a surface scum that looked like a coat of green paint on the surface, that would be an algal bloom,” Filstrup said. “And that just happened within 24 hours. So they are these really rapid, dense blooms of organisms that are really hard to predict.”

The concern with these algal blooms is that some of them can produce potent toxins that attack the liver and nervous system.

“I worked with a Girl Scout several years ago on her Silver Award. And what she wanted to do was create a video on cyanobacteria hazards to warn people her age about them. Because she went to visit her grandparents’ cabin and her dog died from swimming in a lake that had cyanobacteria blooms. And she had never heard of them before,” Filstrup said.

WHEN IN DOUBT, STAY OUT

Not all algal blooms prove to be deadly, but it’s important to approach any green water with caution.

“The Minnesota Pollution Control Agency has the motto “When in doubt, stay out,” Filstrup said, “Keep your pets out of it. If your pets go in it, when you get them home, wash their fur with water.”

In recent years, blooms have formed on Lake Superior’s south shore. “The interesting thing we know about the cyanobacteria that grow within Lake Superior is that they can’t produce toxins. So that’s a good thing,” Filstrup said.

Even blooms that aren’t toxic to us and our pets can affect an ecosystem by taking away the water’s oxygen. Filstrup said, “So it could lead to issues with hypoxia and fish kills just by reducing those oxygen levels.”

Algal blooms are common in southern Minnesota, but in the Northland, we’re entering new territory.

“It is an increasing problem in some of the remote forested lakes in the Boundary Waters Area. And these are lakes where we shouldn’t be seeing algal blooms,” Filstrup said.

The greatest concern locally is in the St. Louis River Estuary, and Filstrup is anticipating this may be the worst year yet.

“Come May, June, July, we’re going to be right at peak bloom time in the estuary. And then as we move forward from there, are those going to get worse and just stick around until the end of fall?”

In order for us to get ahead of this rising concern, Filstrup says it will take more research and more resources.

“It’s going to take a big effort from a lot of people with funding to support those efforts to actually make a change that’s going to be big enough to have an impact on cyanobacteria going forward,” Filstrup said.

Austin also addressed the new development of algal blooms on Lake Superior in recent years. He said, “This is a consequence of the fact that the lake is a warmer place now.”

Despite the challenges of this strange winter, those on Crane Lake’s Bear Island can’t imagine leaving, even if the nature of this winter becomes more common in years to come.

“It’s wonderful. It’s the greatest place in the world to be,” Bergerson said, “It’s home.”