This Sunday marked one of the most highly anticipated indicators of spring in Vermont’s Northeast Kingdom — ice out at Joe’s Pond.
Each year, the lake association takes bets on the date ice out will happen. They place a bundle of cinder blocks wired to a wooden pallet on the ice about a hundred feet out on the pond, hooked up to a weatherproof clock. When the cinder blocks drop through the ice, the clock records the time — and that’s ice out.
This year, it happened at 4:02 a.m. on Sunday, April 14.
The competition drew more than 17,000 bets this year, with contestants guessing when the blocks will fall through. Proceeds are used to support water quality and other work at the popular ice fishing and boating destination in West Danville.
And while it wasn’t a record for earliest ice out, it was on the early side, says organizer Michelle Walker.
“It’s getting earlier and earlier,” she said. “We haven’t had an ice out in May in quite some time.”
The record for earliest ice out was April 5, 2010.
“We saw a handful of lakes ice out in early March, which we hadn’t seen before in any of our records."Mark Mitchell, University of Vermont Lake Champlain Sea Grant Program
And because the competition is so hot and the data collected so precise, year over year, it also serves another purpose. And that’s helping climate scientists better understand how lake ice is changing in Vermont in the face of climate change.
“It’s a good indicator for changing temperatures, basically, because the change in air temperatures are going to have those effects on the lake ice cover, both for lake ice out — which we're seeing earlier and earlier ice out dates — as well as for ice in dates, that are occurring later in the year,” said Mark Mitchell, who coordinates the lake monitoring program for the University of Vermont Lake Champlain Sea Grant Program and Vermont Department of Environmental Conservation.
Mitchell coordinates a statewide water quality monitoring program where most of the data is collected by volunteers.
“We rely heavily on citizen science and volunteers around the state,” he said. “We don’t have eyes all around the state to see exactly when these ice outs are occurring, so we rely heavily on volunteers and citizen scientists to report those observations.”
The winter of 2023-2024 marked the warmest year on record for the Northeast, and that meant many of the more than 800 lakes and ponds around the state lost their ice as early as the beginning of March.
More from Vermont Public: Record warm winter all but guaranteed for parts of Vermont, New York
And then something curious happened: Temperatures dropped and many lakes and ponds froze over again, especially in the northern part of the state.
He says a recent study of about 20 lakes across the state showed ice out is happening about a day-and-a-half earlier each decade.
“We saw a handful of lakes ice out in early March, which we hadn’t seen before in any of our records,” Mitchell said.
Mitchell said climate scientists are still trying to understand the myriad impacts a shorter period of lake ice could have on Vermont’s waterways.
Climate is measured in periods of 30 years or more, so in many cases, more data over more time is needed before firm conclusions can be drawn, linking climate change to specific impacts like more frequent cyanobacteria blooms.
However, scientists can say with certainty that when ice out happens earlier, it creates a longer growing season for blue-green algae and phytoplankton, which require sunlight to grow. Vermont is also seeing more extreme rain as a result of climate change, and now sees on average six more inches of rain every year than in the 1960s.
This past summer’s historic floods carried a year’s worth of nutrients into Lake Champlain during the span of just a few days, according to scientists with the Lake Champlain Basin Program. And that all serves as more fuel for toxic algae blooms.
Citizen science is one of the most powerful tools climate scientists have, said Vermont State Climatologist Lesley-Ann Dupigny-Giroux.
She said old diaries from farmers and fishermen are some of the most useful records available to scientists seeking to understand what the climate was like in the distant past.
The contest at Joe’s Pond is like a modern version of that.
“It speaks to the value of what we call documentary records, which are a goldmine for a climatologist, especially a historical climatologist,” said Dupigny-Giroux.
She said what makes these sorts of records so useful, from a scientific perspective, is that they are recorded without an agenda beyond documenting everyday life.
“It’s priceless … because it’s unbiased because you’re taking it just for the sake of taking it,” she said. “I always say that folks who live and work and play on the water are the best meteorologists because they have to be so attuned to everything that the atmosphere is doing. And folks who produce on the land are the best climatologists because they have to know exactly when to plant and what to plant.”
Climate change is happening faster in Vermont than in many parts of the world. At the same time, Vermont’s location — being so close to the northern Atlantic and Hudson Bay and other “centers of action” means the ways in which our climate is changing are complex.
That, layered with a very wrinkly geography of ridges and valleys, means one community could see very different trends than the next.
Burlington is one of the fastest warming cities in the country. And while it may take more time yet for scientists to fully understand what these changes mean for Vermont, they say paying attention — even through an annual competition — is the first step towards learning more and allowing scientists to say with even greater certainty we are experiencing a particular change because of human-caused global warming.
“Every month, every season, every year is another data point. And each one of those data points is what allows us to do what’s called attribution science,” said Dupigny-Giroux, referring to the science of linking extreme events with human-caused climate change. “You cannot do attribution science if you don’t have a historical record.”
“Every month, every season, every year is another data point. And each one of those data points is what allows us to do what’s called attribution science. You cannot do attribution science if you don’t have a historical record.”Vermont State Climatologist Lesley-Anne Dupigny-Giroux
The Vermont Department of Environmental Conservation’s Lakes and Ponds Management and Protection Program has a web form where you can report ice in and ice out data for lakes across the state.
Dupigny-Giroux is also recruiting citizen scientist observers for the national CoCoRaHS or Community Collaborative Rain, Hail and Snow Network, which records rainfall totals around Vermont — data that is critical for understanding how climate change is affecting different communities across the state. Some Vermont counties have just two volunteers collecting data right now.
Back in West Danville, Michelle Walker with the Joe’s Pond Association said the next task will be recovering their contest marker from the bottom of the lake.
“We’re a small organization and it’s run by volunteers,” she said, “and there’s four or five of us that manage this every year. And we’re the ones that distribute the tickets and pick up the tickets.”
She wasn’t aware that their competition was generating such useful science, but she was delighted to hear it. “I had no idea,” she said with a laugh. “But that’s pretty cool.”
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