In the past decade, Lake Superior has become a fascinating case study for scientists and educators in how climate patterns are evolving and impacting our natural world. From record-high water temperatures to shifting ice cover and fluctuating lake levels, the changes in Lake Superior’s weather patterns have been said to be a not only beautiful, powerful, but also potentially concerning.
Warmer Water Temperatures and Declining Ice Cover
Lake Superior has seen consistently warmer water temperatures over the last decade, hitting record highs a few times over that time period. Warmer summers are one of the contributors to higher lake temperatures. Those higher temps can feel pleasant but they actually have a big impact on the lake’s ecosystem. As the air heats up, it fuels evaporation, increasing moisture in the atmosphere and affecting weather patterns around the lake.
This warmth also reduces ice cover in winter. Less ice means the lake stays open longer, making it more vulnerable to evaporation and leading to higher water levels in some seasons and lower ones in others. In the winter of 2020, for example, ice coverage on Lake Superior was notably low, which scientists linked to both warmer winter air and disruptions in the polar vortex, a pattern that typically brings frigid Arctic air southward over the Great Lakes. (sources: GLERL, U.S. Geological Survey, US EPA)
Dramatic Swings in Water Levels Due to Lake Superior’s Weather
Lake Superior’s water levels have fluctuated greatly. In the early 2010s, they were on the low side, only to rise dramatically to near-record highs by 2019. What’s causing this rollercoaster? Scientists state that climate change plays a role by influencing how much precipitation falls in the area and how quickly it evaporates. Recent years have seen more intense spring rains, filling the lake fast, followed by dry spells where levels drop back down as the lake “breathes” through evaporation. These fluctuations create challenges for managing shoreline erosion and maintaining habitats around the lake. (sources: Great Lakes Echo, GLISA)
Related: Does Lake Superior have “tides”
Snowfall and Lake-Effect Snow
Lake Superior’s warming waters also have a hand in winter snowfall patterns according to experts. As cold air passes over the warmer lake in early winter, it picks up moisture, fueling intense lake-effect snow. This has made snowfall heavier and more unpredictable in regions downwind of the lake, like Michigan’s Upper Peninsula and northern Wisconsin. Some years have seen incredible snowfall, while warmer winters brought less. This variability affects not only local life but also regional tourism, as many people travel to the area to enjoy winter sports. (sources: GLISA, U.S. Geological Survey)
Lake Superior, like the other Great Lakes, is showing us how climate change doesn’t just mean a slow, steady warming — it can also mean more dramatic shifts in temperature, snowfall, and water levels, sometimes within just a few years. Watching how this mighty lake responds by monitoring Lake Superior’s weather can give scientists insight into the future of other freshwater ecosystems.
