Runaway Buoy Reveals Rare Winter Wave Data: 8-Foot Waves Detected Under Lake Ice

Winter usually brings a lull to field work on the Great Lakes: research vessels stay tied to docks and many instruments come ashore. Last winter, an unexpected exception produced rare, continuous offshore observations.

A basketball-sized research buoy deployed off Muskegon, Michigan, in late summer 2023 broke free from its mooring in mid-January and drifted roughly 33 miles toward the center of Lake Michigan. While adrift the instrument continued transmitting temperature and wave-height data through the heart of winter.

Unique Measurements From a Rogue Buoy

The buoy drifted back toward shore and became lodged in progressively thicker ice south of Grand Haven. That movement gave scientists a rare gradient of conditions — from open water to fractured ice and then to a solid ice sheet — in a single instrument record.

During a severe storm on Feb. 7–8, the buoy recorded waves taller than eight feet beneath a section of solid ice. Those measurements indicate that existing models dampen ice-covered waves too strongly: modeled wave heights under ice were substantially lower than the buoy’s observations in open-lake conditions.

“It just aligned perfectly with the kind of work we were trying to do,” said Steve Ruberg of NOAA’s Great Lakes Environmental Research Lab.

Why This Matters

Direct winter observations from the middle of the lakes are scarce because research vessels and search-and-rescue craft cannot safely operate in storms. The new buoy data help fill critical gaps that affect forecasts for commercial shipping, shoreline planning, and coastal erosion assessments — issues that matter increasingly as storms grow stronger and ice cover patterns shift with climate change.

Recovery and Next Steps

The buoy washed ashore north of South Haven on March 25; a local resident hauled it up shortly thereafter, and NOAA researchers recovered it in early April. Analysts are now comparing the buoy record with existing wave-and-ice models and regional observations (for example, in Saginaw Bay, where models perform better because ice conditions are more stable).

Researchers are also using advances in technology and deployment techniques to expand winter monitoring. Teams have begun air-dropping larger buoys by helicopter into Lake Superior and northern Lake Huron and Lake Michigan, and scientists are exploring underwater robots and more robust sensors to close the winter data gap.

Bottom line: A lost buoy has provided one of the first direct looks at how waves and lake ice interact in winter open water — revealing that models need improvement and highlighting the value of new technologies for year-round monitoring.