Vermont DEC Seeks Lake Ice Observations from the Public

Montpelier, Vt. – As Vermonters patiently wait for spring temperatures, the Department of Environmental Conservation (DEC) invites the public to report when Vermont’s lakes and ponds lose their ice cover. Also

known as the “ice-out date,” this date marks when lakes or ponds become ice-free from shore to shore. Tracking ice-out dates helps DEC scientists decide when to begin seasonal water quality sampling efforts.

“Keeping track of ice-out dates in Vermont helps us to better understand how climate change impacts our lakes and ponds,” said DEC Commissioner Jason Batchelder. “Our scientists can learn about and track statewide and regional climate trends by using these long-term records of lake ice.”

When ice covers lakes, the water below separates into layers based on temperature and density. When the 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.

“Since 1977, we have collected information on the spring water quality of lakes larger than 10 acres in size,” says Mark Mitchell, a limnologist with DEC and Lake Champlain Sea Grant. “Over those 48 years, we have seen trends of earlier lake ice-out dates across Vermont and New England, which can be a sign of climate change.”

You can report lake ice observations using the DEC’s Lake Ice 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 famous and long-running ice-out contest sites include Joe’s Pond in Danville, Lake Iroquois in Hinesburg, and Lake Memphremagog. These contests are an engaging way for lake associations and communities to encourage folks to observe lakes and ponds throughout the year.

To find spring water quality information, view the Vermont Lake Score Card. For more information, visit the DEC Lakes and Ponds Program.