Sentinels of the Lake: How Data Buoys Increase Safety and Support Communities of Wisconsin's Lake Michigan

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May 2025

Just off the shores of Sheboygan, Wisconsin, the Shipwreck Sentinel quietly bobs in the waves—one of many data buoys deployed across the Great Lakes. Sitting within the waters of Wisconsin Shipwreck Coast National Marine Sanctuary, this data buoy provides valuable information used by fishers, boaters, and surfers alike. Since its designation in 2021, the data collected by the buoys in Wisconsin Shipwreck Coast National Marine Sanctuary have been viewed over 270,000 times online—providing a vital service to the surrounding community.

From Deadly Waters to Real-Time Warnings

​Lake Michigan has a reputation for being one of the most perilous of the Great Lakes, with numerous ships having foundered here over the centuries, and a significant number of drownings reported annually. According to the Great Lakes Surf Rescue Project, between 2010 and 2024, there have been over 1,300 drownings across the Great Lakes. Lake Michigan consistently accounts for a substantial portion of these incidents.​ To address this issue, buoys are being deployed with cutting edge technology capable of transmitting data in real-time.

Since 2022, three compact, solar-powered Sofar Ocean Spotter buoys and the Shipwreck Sentinel have been deployed each season, covering more than 70 miles of Wisconsin's coastline. They provide real-time updates on water temperature, wave height, and wind speed—critical data for lakefront communities and mariners alike.

According to Wisconsin Shipwreck Coast National Marine Sanctuary Superintendent Russ Green, logging these values over long-time periods helps fill a void in Lake Michigan that was present before the sanctuary was designated.

“We saw real-time platforms increasing across the Great Lakes, but there was a gap in mid-Lake Michigan,” explains Green. “It made sense to fill that data gap and at the same time provide valuable safety information to boaters.”

Accurate weather forecasting is vital not only for local economies across the Great Lakes, but also public safety along the shores. Lead Meteorologist Kevin Wagner at the National Weather Service in Milwaukee, Wisconsin, notes how this data is utilized every day in creating weather forecasts.

“We heavily rely on buoy data. The Shipwreck Sentinel buoy is one of the few observations that provide consistent water data in the middle section of Lake Michigan during the most active time of the year,” says Wagner. “It serves as an additional observation point for identifying small craft conditions, gale force gusts, and thunderstorm hazards over the waters, which helps us issue associated advisories, watches, and warnings.”

With the multitude of sensors installed on the data buoys, they help not only forecast weather patterns, but also provide data for local surf reports and potentially hazardous wave conditions. For those navigating Lake Michigan, such as commercial fishing and shipping vessels or recreational fishermen, the waters can change from calm to dangerous in a short amount of time. With these data buoys now in place transmitting real-time data, vessels can now easily adjust their routes or schedules to help avoid any upcoming rough weather in their area.

Green explains that the sanctuary prioritized these buoys in the early days after sanctuary designation not just for weather and long-term monitoring data, but because they would make on-water recreation safer. But the real-time data buoys aren't the only way that the sanctuary is making the waters safer for recreation users. In 2024, the sanctuary installed mooring systems and marker buoys at 24 popular shipwrecks sites.

“The moorings increase public access to shipwrecks, support recreation such as paddling, snorkeling, and diving, and protect nationally-significant historic sites from anchor damage,” states Green. The sanctuary will re-deploy these buoys each year from approximately May through October to keep both the people on the water and the resources the sanctuary protects safe.

A Network of Service

All of the data collected by the real-time data buoys is sent to and compiled by the Great Lakes Observing System, or GLOS for short. The three spotter buoys were funded by GLOS through a grant the sanctuary wrote, while the Shipwreck Sentinel was funded through a grant from the Fund for Lake Michigan.

A part of the larger Integrated Ocean Observing System led by NOAA, GLOS manages the lake data to provide it to the general public in an easy-to-digest format. All of the data is made available through their website called Seagull, which provides an overlay of the Great Lakes with forecasts on water temperature, current, ‘omics data, and more. When looking at Seagull, you will see that two other Great Lakes sanctuaries, Thunder Bay National Marine Sanctuary and Lake Ontario National Marine Sanctuary, are home to data buoys as well!

Real-Time Tools for Anglers

By using the Seagull website or phone app, anyone can find this valuable information in just a few clicks. For example, the buoys are extremely popular among fishermen—with some fishing organizations even sponsoring new buoys to be deployed.

Captain David Lutze is the owner of Playin' Hooky Charters and has spent the last 19 years in the charter fishing industry, and is a member of the Sheboygan Area Great Lakes Sportfishermen.

“The water temperatures can change drastically so it's nice to know before we leave the dock how the water temperatures were affected by the wind,” says Lutze. “I think that the buoy is very popular since I believe everyone who knows about it in Sheboygan utilizes it often during the season. I personally sometimes check it multiple times a day.” Lutze also added that as a charter captain, it can be helpful to get wave direction and interval information from the buoy to ensure his guests will be comfortable while on the water.

While fishermen may check a variety of sources for wind speed, such as the lighthouse in Sheboygan, Lutze explains that the wind data from other sources is sometimes different than what the buoy provides. “There is nothing to block wind out on the lake,” says Lutze. This makes the on-water buoy a more reliable and accurate source.

Aside from wind data, fishermen are also interested in finding a particular depth to fish within the water column known as the “thermocline,” the depth where the warm water transitions to the cooler water below. This also happens to be a depth where fish such as coho salmon or rainbow trout like to stay in Lake Michigan.

The buoys are equipped with vertical strings of sensors that measure water temperature every one to two meters. With this information, fishermen can easily identify the location of the thermocline. Equipped with the data from the buoys, fishermen can set their lures to the perfect depth to maximize their chances of getting a fish on the line.

Surfer's Forecast: Catching Waves with Data

Fall is peak wave season on Lake Michigan as strong winds and low-pressure systems move across the Great Lakes more frequently in fall, creating larger, more consistent waves. Given the unique geography of Sheboygan, it is a popular surfing destination right on the shore of Lake Michigan. Many surfers even refer to these waters as the “Malibu of the Midwest.” Strong southern winds also make the sanctuary's central beaches a hotspot for kiteboarding.

The data buoys give these watersports enthusiasts a good idea of what to expect on the water, and helps them know when the conditions are right for their chosen activity. Seagull provides forecasts for both water current and wind speed, and having the Shipwreck Sentinel right off the coast of Sheboygan ensures up-to-date and accurate predictions. When the surf's up, don't be surprised to see people riding pretty big waves—even when the water is only 33 degrees Fahrenheit.

The People and Work Behind the Buoys

These reliable and useful buoys don't just maintain themselves. Given the continental climate of Wisconsin, the buoys are removed from Lake Michigan every fall and redeployed every spring. In Wisconsin Shipwreck Coast National Marine Sanctuary, NOAA and University of Wisconsin researchers deploy and recover the Shipwreck Sentinel every year aboard one of the Great Lakes Environmental Research Lab's vessels and bring it to the University of Wisconsin for storage, maintenance, and repairs at their facility. Maintenance involves everything from recalibrating the sensors to cleaning off the fouling organisms that were growing on the buoys. Michigan Tech University is in charge of maintaining the three spotter buoys. This collaboration offers unique experiences to students in aquatic programs at the two universities.

The University of Wisconsin - Milwaukee School of Freshwater Sciences deploys and maintains over 10 buoys annually across Lake Michigan and Lake Superior. Jessie Grow is in charge of these larger floating data platforms and is constantly looking to learn and improve them.

“Recent improvements include upgrading obsolete data loggers, switching to more efficient solar controllers, waterproofing electronics housings, and upgrading surface cameras,” says Grow. “This work involves a lot of planning—schematics, rewiring, and trying to fit everything into a tight, watertight enclosure. GLOS supports this work by helping with data management, system integration, and making sure the information from the buoys is accessible and useful for scientists, mariners, public safety officials, and the public.”

A Sanctuary Powered by Science and Service

Every day, real-time data collected by NOAA and its partners is helping people stay safe and informed. Whether you're casting a line, catching a wave, or checking the local forecast, the data buoys deployed in Wisconsin Shipwreck Coast National Marine Sanctuary are quietly working behind the scenes to keep people safe on and near the water. These advanced monitoring platforms are more than just floating instruments—they represent NOAA's commitment to science, safety, and public service.

As the only national marine sanctuary in Lake Michigan and one of only three on the Great Lakes, this sanctuary is uniquely positioned to bring many partners and resources together to deliver critical, real-time data for local communities and regional decision-makers alike. NOAA's stewardship ensures that this information remains accessible, reliable, and useful—not just for recreation and weather forecasting, but for advancing scientific understanding of the Great Lakes for generations to come.

Thanks to NOAA's leadership and the many partners who make this possible, real-time lake data is now within everyone's reach.

Want to check current lake conditions or learn more about the buoys in your area? Visit Seagull by GLOS to access real-time data on water temperature, wave height, wind speed, and more across the Great Lakes—including the Shipwreck Sentinel.

Daniel Wroblewski is a science communication intern for NOAA's Office of National Marine Sanctuaries and a student at the University of Wisconsin-Milwaukee School of Freshwater Science

Rachel Plunkett is the content manager and senior writer/editor for NOAA's Office of National Marine Sanctuaries

This work is authorized under the National Marine Sanctuaries Act (16 U.S.C. §§ 1431(b)(4) and 1433), which directs the Secretary of Commerce to enhance public awareness and wise use of the marine environment, and to facilitate scientific research and compatible public use of national marine sanctuaries.