Michigan scientists have compiled a new dataset tracking ice cover on the Great Lakes since 1897, using historical temperature records. This resource is aiding studies on climate impacts and declining species like lake whitefish. The data also promises to enhance winter ice forecasting for safety.
In a bid to better understand the Great Lakes' winter dynamics amid climate change, researchers from the University of Michigan and the Michigan Department of Natural Resources have created a comprehensive dataset on ice cover spanning from 1897 to the present. By analyzing consistent temperature records from regional weather stations, the team calculated ice formation and duration over this 120-year period. The findings, published last month in the journal Scientific Data, fill a critical gap in historical winter data, as direct observations like satellite records only date back 45 years.
The dataset serves multiple purposes. It deepens insights into how rising temperatures—up in the region over the last two decades—have shortened frost seasons and increased extreme weather events such as heavy snow and rainstorms. For instance, it provides a baseline for examining the historic decline of lake whitefish, a species vital to the area's culture and economy. Lead author Katelyn King, a fisheries research biologist, noted, “A lot of the biological conditions under ice are really poorly understood.” She is already applying the data to her whitefish studies.
Co-author Ayumi Fujisaki-Manome, associate director at the Cooperative Institute for Great Lakes Research, emphasized the broader significance: “Lake ice is really part of the system, part of our life. It matters [for] our culture, regional weather, safety, everything.” The information could improve ice cover predictions, benefiting recreation and safety on the lakes.
Recent variability underscores the dataset's timeliness. Last winter's ice cover was near average after a historic low the previous year, while this season has seen some of the highest levels in years due to recent cold snaps, according to National Oceanic and Atmospheric Administration data. King observed, “These really extreme years where we have really cold weather or really warm weather is just a sign that long-term climate is changing. It really affects all of us in our day-to-day.”
