Two Yellow Buoys is now an award-winning Twitter feed

July 20th, 2017 by

Illinois-Indiana Sea Grant’s two Lake Michigan real-time monitoring buoys know that they’re popular. And if you follow the Twitter account, @TwoYellowBuoys, they’ll tell you so.

Part of this popularity may be because the buoys are festive. In addition to decking themselves out for holidays.


4th of July



Alternatives to Easter egg hunts.


Or maybe it’s because the buoys are clearly in love with science so they share interesting data patterns.



Here they introduce themselves to Bill Nye, the Science Guy.


The buoys’ hard work informing people about conditions in southern Lake Michigan was recognized with an APEX Award of Excellence for Social Media – Sites. This is the second IISG project to win a 2017 APEX Award. The buoys are proud to work alongside their Sea Grant colleagues, serving the people who live and recreate in southern Lake Michigan.

*The buoys would like to thank IISG Assistant Research Coordinator Carolyn Foley for managing their Twitter account. They also blame Carolyn for any mistakes made, because they’re buoys. It’s difficult to Tweet when you don’t have arms.

If you love the buoys, let them know!

The buoys take the winter off for some well-deserved pampering

November 3rd, 2015 by

Every year as winter approaches, the Michigan City and Wilmette buoys are taken out of Lake Michigan. So we were wondering, what happens to them? Where do they go? The best people to tell us about the off-season lives of the buoys are the individuals who work the closest with them — IISG Assistant Research Coordinator Carolyn Foley and Aquatic Ecology Specialist Jay Beugly. Here’s what they had to say.

Why do we need to take the buoy out? Why can’t it stay in all year? The main reason to take the buoy out is that the lake ices over in the winter. Weather conditions when there is not ice can also get very, very rough — rougher than what the buoy is meant to withstand (though we’re always trying to make things stronger and more rugged). The delicate instruments that take measurements also need to be cleaned and maintained to be sure we can keep transmitting the best data possible.

Is it hard to get it out? It must weigh a lot! How many people does it take? It is much easier to retrieve the buoy at the end of the year than to put it out in the springtime. You usually need one person to captain the boat and 4-5 people to help pull up the ballast weights and stop the buoy from bouncing against the boat.

Where does the buoy go once it’s out? A warehouse? A garage? The buoys are usually stored at the Purdue University West Lafayette campus, in the Civil Engineering building. Sometimes they are stored at LimnoTech’s headquarters, in Ann Arbor, MI. The buoys tend to move around during the winter, especially if they need upgrades. So keep your eye out for buoys on trailers when you’re travelling down I-65 or I-94.

Aquatic species attach easily and quickly to things in the water. Has that ever happened to any of the buoys? What did you do? Every year! Quagga mussel veligers floating around Lake Michigan are always looking for hard structures to attach to, and even if we only put the buoy out for one month, we find young quaggas that have attached themselves. Though some of the surfaces on the buoy are smooth enough to stop the quaggas from attaching, they always manage to find their way into nooks and crannies. We carefully inspect the buoy before leaving the lakeside and remove anything we see, either manually or with help from a hose.

Does the buoy get a tune-up? Like a thorough wash-down? A paintjob? The main hull gets cleaned off and all of the sensors are removed and cleaned. Depending on the sensor, this may mean an acid wash or just a good wipe down. One year we had to replace a solar panel that had completely fallen off, so we’re always double-checking that everything is where it’s meant to be.

What happens to the buoy website? Is all the archival data still available? The IISG buoy data websites go offline while the buoys are not in the water, but the main IISG buoy pages are still active. Historic data can always be found at the NDBC page (buoys 45170 and 45174, respectively), and at People who want to use the data should pay attention to notes like “Data have not been quality-checked” – if the data haven’t been quality-checked, they may contain really weird, fluke readings (like the 100-foot wave that the Michigan City wave height sensor recorded in 2014). We try to quality check the whole year of data within a few months of retrieving the buoy. People are also always welcome to email us to ask questions about the data.


Breaking news: Michigan City buoy returns for fourth season

April 28th, 2015 by
Swimmers, boaters, and anglers visiting Indiana’s coastline can once again learn about conditions in southern Lake Michigan with real-time data collected by the Michigan City buoy. The buoy, launched for the first time in 2012, returned to its post four miles from shore today to collect data on wave height and direction, wind speed, and air and surface water temperatures. 
The only one of its kind in the Indiana waters of the lake, the Michigan City buoy and its temperature chain helps anglers and boaters find fishing hot spots and identify the safest times to be out on the lake.  
Scientists at the National Weather Service in northern Indiana will also use wave height and frequency data collected throughout the season to better anticipate the locations of strong waves and currents that cause dangerous swimming conditions. Real-time data on nearshore temperatures and wave characteristics is also vital for research on fisheries and nearshore hydrodynamics
Data will be available on IISG’s website until the buoy is pulled out for the winter in mid-October. The site shows snapshots of lake conditions—updated every 10 minutes—as well as trends over 24-hour and 5-day periods. Buoy-watchers can also download raw historical data at NOAA’s National Data Buoy Center
And starting later this season, our website will also relay data collected by a new environmental sensing buoy placed north of Chicago. In addition to allowing people to track waves and temperatures, the data collected by this buoy could also help officials warn beachgoers when contamination levels may make swimming unsafe. 

Nearshore buoy coming to Illinois summer 2015

December 2nd, 2014 by

A new environmental sensing buoy will be placed north of Chicago this summer, making it easier than ever for Illinois boaters and beach-goers to spend a fun, safe day on the water. 

Michigan City Buoy

Like its counterpart in Michigan City, IN, the nearshore buoy will relay information on wave height and direction, wind speed, and air and surface water temperatures in near real time. A webcam will also make it possible to watch changing lake conditions first-hand.

This is the newest in a string of nearshore buoys along the Lake Michigan shoreline. In addition to allowing people track waves and temperatures, the data they collect will help officials warn beachgoers when contamination levels may make swimming unsafe. Researchers also rely on the real-time information to manage fisheries, monitor lake currents, and improve hazardous weather predictions.


The Illinois buoy, jointly operated by IISG and LimnoTech, is expected to go online in May. The project is funded by the Great Lakes Observing System through a grant from NOAA Coastal Storms. 
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