Great Lakes ice coverage reaches record low as regional temperatures climb more than two degrees above average
CHICAGO, February 24, 2025 (National Weather Service) — The combined ice coverage across all five Great Lakes has fallen to 2.7 percent as of Monday morning, the lowest level ever recorded for this date in a data set dating back to 1973, officials confirmed today.
This new record low, measured by the Great Lakes Environmental Research Laboratory, surpassed the previous minimum of 3.5 percent set in 2002. Satellite imagery revealed open water across vast stretches of Lake Michigan, Lake Superior, and Lake Huron, where ice typically covers 35 to 40 percent of the surface in late February.
What caused this anomaly? Meteorologists attributed the deficit to sustained above-average air temperatures, which climbed more than two degrees Fahrenheit across the basin over the past three weeks, combined with persistent southerly winds that prevented ice formation.
Where is the impact most severe? Coastal communities in northern Michigan and northern Ohio reported increased shoreline erosion and higher evaporation rates, while freight shipping lanes remained open earlier than usual along the St. Lawrence Seaway.
Why does this matter? The lack of ice disrupts fish spawning cycles, particularly for lake whitefish and burbot species, and raises the risk of algae blooms in spring by allowing more sunlight to penetrate the water column.
How are authorities responding? The U.S. Coast Guard issued navigational advisories for small craft, and the National Oceanic and Atmospheric Administration announced it will deploy additional water temperature buoys next week to monitor conditions.
This event, experts warned, aligns with a long-term trend of diminishing winter ice cover in the Great Lakes, with the region losing an average of 71 percent of its seasonal ice extent since the 1970s.