CFL Education on Frozen Lakes Spans Wisconsin
During the winter, many Wisconsinites share in the joys of a frozen lake or other waterbody. Ice fishing, ice skating, skiing, snowshoeing, and snowmobiling are all popular types of frozen fun. The Center for Limnology also deeply enjoys this season, continuing research under the ice and leading educational activities on top of it.
Each February, the CFL participates in Clean Lakes Alliance’s Frozen Assets Festival on Lake Mendota in Madison. For a decade, we have set up an ‘Ice Lab’ and demonstrated limnology methods with visitors. We drill holes in the ice and measure its thickness, while talking about ice safety, then use a Secchi disk to show how clear the water usually is (at least when compared to the summer). Our activities also include testing different local water samples, including tap water, to show how salty they can be. Often, we set up ice fishing or collect zooplankton, tiny crustaceans that live in the water, for show and tell.
This year, we also presented information comparing Lake Mendota to Antarctic lakes (spoiler alert- Antarctica has way more ice), with Dr. Hilary Dugan and graduate student Kayla Hubbard talking about their experiences working there. Hilary was also interviewed by NPR for a recent podcast about lakes in winter and how they are changing. For example, just two years ago, the lake ice was so thin that the whole event had to be moved onto land.
We also had a melting ice demonstration this year, where we collected a block of ice from Lake Mendota and placed it under heat lamps for a few hours. This shows how ice can melt internally in vertical channels, or “candle,” and ultimately become unsafe for traveling or recreating on. We dripped some green food coloring onto the ice block to highlight this effect.
2026 was a great year for our event. We had comfortable weather, snow for good traction, about 45 cm of ice thickness (1.5 feet), and more than 300 visitors that stopped by our station! Thank you to Clean Lakes Alliance and all the people who joined us for this annual opportunity to engage in fun science on the ice.
Further north in Boulder Junction, Wisconsin, Trout Lake Station held its annual Schoolyard Winter Limnology event earlier this month for 4th and 7th graders in the Northern Highlands region. Since around 2000, Schoolyard has been the key educational element of the CFL’s North Temperate Lakes Long Term Ecological Research program (NTL-LTER) and has introduced more than 2,500 students in northern Wisconsin to the science of limnology with hands-on learning on the ice, in the lab, and in the classroom.
A group of 7th graders from four local schools joined TLS researchers for one day on station and then all the 4th graders from one school joined for another day. This year, we had extremely good weather, 52 cm of ice thickness (around 1.75 ft), and a great level of energy and enthusiasm all around.
Students learn all about the lake by using various equipment, collecting zooplankton and benthic samples, taking temperature and dissolved oxygen readings, and a crowd-favorite- sticking their hands in shortening-coated bags to simulate how fat insulates animals in the water. They also examine fish forms, use microscopes to see zooplankton up close, watch an ice candling demonstration, and express their creativity with drawing, among other lake-themed activities. Thank you to all the Schoolyard collaborators for another fantastic year.
The CFL greatly appreciates the opportunity to educate people about science on frozen lakes across Wisconsin, especially as our winter to spring transition is becoming less predictable. Lake Mendota has already been thawed since March 13, with strong winds driving the water open. That means Mendota was frozen for 71 days this winter, which is on par with the last five-year running average. By contrast, Trout Lake is still frozen and will likely remain so for another month. Its average ice-off date is April 24. Residents of the northern part of the state hopefully get to enjoy winter’s activities for a little while longer. As spring officially kicks off, we reflect on our frozen fun and will see you back on the ice next winter for more!