State asks Vermonters to report on spring changes in lake ice
March 24, 2023 | By Waterbury Roundabout 
Lake Champlain ice cover seen from Red Rocks Park in South Burlington on May 17, 2022. Photo by Mark Mitchell.
As Vermonters patiently wait for spring temperatures to arrive, the Department of Environmental Conservation asks Vermonters to report when Vermont’s lakes and ponds lose their ice cover. The date when lakes or ponds become ice-free from shore to shore is often referred to as the “ice-out date.”
Tracking ice-out dates helps state environmental scientists decide when to begin seasonal water quality sampling work.
“By reporting ice-out dates, Vermonters can help us better understand how climate change impacts our lakes and ponds,” said Department of Environmental Conservation Commissioner John Beling. “Using long-term records of lake ice, our scientists can learn about and track statewide and regional climate trends.”
When ice covers lakes, the water below separates into layers based on temperature and density. When surface ice fully melts in the spring, the heavy cold water sinks and the water column fully mixes. Water samples collected at this time of mixing show the baseline amount of phosphorus a lake will have available to fuel algae and aquatic plant growth during the spring and summer.
A Vermont Department of Environmental Conservation scientist collecs water samples on Molly’s Falls Reservoir in Marshfield shortly after ice-out in early spring. File photo courtesy VT DEC
“Since 1977, we have collected information on the spring water quality of lakes larger than 10 acres in size,” says Mark Mitchell, a state limnologist.“Over those 45 years, we have seen trends of earlier lake ice-out dates across Vermont and New England, which can be a sign of climate change.”
Members of the public can report their lake-ice observations using the online reporting form. Many lake communities around the state also hold ice-out contests, usually in the form of a raffle where the winners can receive prizes or cash. Some of the more popular and long-running ice-out contests are on Joe’s Pond in Danville, on Lake Memphremagog along the Vermont-Canada border, and on Lake Iroquois in Hinesburg.
To view spring water quality information, visit the Vermont Lake Score Card. For more information visit the DEC Lakes and Ponds Program online. The Department also has accounts on Facebook and Instagram.