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Ethereal ice swirls alongside Chicago during polar vortex cold snap
Summary
A satellite image captured rippling ribbons of ice on Lake Michigan beside a snow-covered Chicago during a Jan. 19–24, 2025 cold snap linked to a sudden polar vortex expansion; about 20% of the lake was iced over when the photo was taken, GLERL reported.
Content
This satellite image shows rippling ribbons of ice moving across the surface of Lake Michigan near a snow-covered Chicago during an intense mid-January cold snap. The event followed a sudden expansion of the polar vortex, which brought unusually low temperatures and strong offshore winds to the region. Those conditions encouraged coastal ice to form and be pushed outward, producing flowing, cloud-like patterns in the ice. The scene was noted by NASA's Earth Observatory and regional researchers as an uncommon surface pattern for this time of year.
What we know:
- The image shows rippling, ribbon-like ice formations on Lake Michigan alongside snow-covered shoreline near Chicago, described by NASA's Earth Observatory.
- The cold snap occurred between Jan. 19 and Jan. 24, 2025, and NOAA reported temperatures in Chicago as low as minus 33 degrees Fahrenheit (minus 36 degrees Celsius).
- About 20% of Lake Michigan was covered by ice when the satellite photo was taken, according to NOAA's Great Lakes Environmental Research Laboratory (GLERL).
- Strong offshore winds helped push coastal ice outward, creating flowing ribbons and thicker offshore ice with rough, whiter edges, as explained by GLERL ice researchers.
- Other Great Lakes were affected too; GLERL reported up to 80% ice on Lake Erie, and the New York Times reported a Canadian cargo freighter became trapped for three days during the event.
Summary:
The image highlights how a sudden polar vortex expansion, very low temperatures, and strong winds combined to produce unusual flowing ice patterns on Lake Michigan in mid-January. Researchers reported the lake was about 20% iced over at the time and noted heavier ice on nearby lakes; Undetermined at this time.
