Ice shanties sit along the shore of Little Ossipee Lake in Waterboro on Friday. The lake is beginning to freeze but has open water in many spots. Shawn Patrick Ouellette/Portland Press Herald
Last winter, Salmon Lake was iced over for just 67 days. That’s the shortest ice season in the 34 years that retired Colby College professor Lenny Reich has recorded the freeze and thaw dates on a support beam in the basement of his lakeside home in Belgrade.
“In a few decades, there won’t be much ice at all, certainly not enough to safely fish or snowmobile,” he said. “The lack of winter ice only exacerbates warming because snow and ice reflect the sun, while open water absorbs sunlight, and as a rule, a hot lake is not a healthy lake.”
Maine lakes are warming two times as fast as the air around us, according to the Maine Climate Council. Since the 1980s, the lakes of northern New England have been warming, on average, about 1.4 degrees Fahrenheit per decade.
The blast of cold air that arrived late last week is expected to last through this week and help freeze over lakes and ponds that still have thin ice and, in many cases, open water. State officials warned residents last week to be careful and check ice thickness after people fell through thin ice, including a 68-year-old man who nearly died on New Years Day in Franklin County.
Salmon Lake — which last winter iced over Jan. 8 and iced out on March 15, according to the support beam records in the basement of Reich’s home — offers a peek at the rapidly warmer future that awaits Maine’s ponds, lakes and rivers.
Ice-in dates for Maine’s freshwater bodies are hard to come by — it can be hard to detect when the final freeze occurs — and ice-in doesn’t mean it’s solid enough to safely skate or fish. But Maine has a century-old record of ice-out dates that show freshwater thaws are happening earlier, said state climatologist Sean Birkel.
“Ice out on Maine lakes is occurring 1-2 weeks earlier on average now compared to what was typical in the 1970s,” Birkel said. Given Maine’s rising fall temperatures, he noted, it’s likely that ice-ins are happening later, too, even if there is no broad historical data. “November and December have both warmed and many have observed lakes freezing later.”
There can be considerable variation across the state. The ice-out date for Acadia National Park’s Eagle Lake is only one day earlier than it was in 1960, while western Maine’s Worthley Pond is now thawing out 25 days earlier, according to the 2020 Maine’s Climate Future Report from the University of Maine.
Scientists first recorded this trend two decades ago. In 2002, two federal geologists combed newspaper reports to gather ice-out dates for 29 New England lakes and revealed they were happening between 9 and 16 days earlier than they did in 1850.
Averaging ice-out dates from Maine’s more than 300 ponds and lakes suggest the change is speeding up. Over the last 20 years,