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In warming winters, a new method of preserving snow for skiing

Paul Bierman and Judy Geer checked snow saved from last winter for use on trails at the Craftsbury Outdoor Center in Craftsbury, Vt.Caleb Kenna for The Boston Globe

CRAFTSBURY, Vt. — In the Northeast Kingdom of Vermont, a bucolic magnet for cross-country skiers, winter temperatures have been rising, snowfall has been dwindling, and a sport that is a driver of the state’s winter economy faces a perilous future.

But at the Craftsbury Outdoor Center, about 30 miles from Canada, a first-time experiment in the United States is seeking to preserve more of the Nordic ski season and turn bare trails into ribbons of snow.

The bold experiment, conducted with the University of Vermont, seems impossible: Store large mounds of snow outside, all through the summer, and have enough survive to spread around when the season opens near Thanksgiving, when snow is increasingly unpredictable.


But perhaps a snowball does have a chance in devilish climes. This year, there was enough snow left to cover between 2 and 3 kilometers of Craftsbury’s trails, a breakthrough that bodes well for the method’s potential.

“We’re really excited,” said Hannah Weiss, a UVM graduate student, pumping her fists when she described the result. “We didn’t know what to expect.”

Similar to commercial ice harvests of long ago, when sawdust kept blocks of ice frozen, UVM’s scientists and their Craftsbury partners did the trial-and-error trick with a blanket of wood chips topped by reflective fabric.

As a result, the center still had 6,000 cubic meters of snow — more than 60 percent of the original supply — rising from a dry, 17-foot-deep pond after the leaves had turned in far northern Vermont.

“We’ll be perfecting this and learning,” said Judy Geer, who directs the nonprofit outdoor center with her husband, Dick Dreissigacker. “We’re trying to stay ahead of the curve.”

Snow storage has been tried in Europe and a few places in Canada, but never at such low elevation and latitude, making the Craftsbury project a possible bellwether for the industry.


“Lake ice is shrinking. The snow pack is shrinking. It’s becoming more difficult economically for ski areas to make a go of it,” said Paul Bierman, the UVM geology professor who oversees the project.

“This is something that can be applicable all over Vermont,” Bierman said of the experiment. “It can buy us a decade or two of Nordic skiing.”

That might not sound like much of a reprieve, but such is the accelerating pace of climate change, Bierman said.

In 2003, Vermont recorded 115.9 days with at least one inch of snow cover, according to state government statistics. By 2013, that number had plummeted in a drastic, downward track to 22.5.

“It’s changing fast,” said Bierman, who has studied the history and melting of Greenland’s ice sheet. “And every prediction we look at, we’re following the worst-case scenario of carbon emissions.”

Downhill ski areas also have been planning for less natural snow, but their higher elevation and higher snowfall help mitigate the existential threat that confronts many lower-lying Nordic facilities. Craftsbury, for example, is about 900 feet above sea level.

University of Vermont professor Paul Bierman explained how snow from last winter was saved over the summer for use on ski trails this season.Caleb Kenna for The Boston Globe

Steve Howell, a Nordic skier from Woodstock, N.H., paused near Craftsbury’s many trails and acknowledged that climate change could alter the sport.

“The stronger places will survive, but the mom-and-pop operators might perish,” Howell said.

That contraction already is occurring. The number of Nordic skiing venues in New England has shrunk to 60 from 200, according to Preston Noon, operations manager for the New England Nordic Ski Association.


Bierman said the experiment took flight while he was standing in his cross-country skis, chatting with Geer during one of his many visits to the 500-acre center, which also offers warm-weather options such as rowing, cycling, and running.

“We just started talking about the possibility of storing snow, probably on a day when there wasn’t much snow,” Bierman said with a chuckle.

A partnership was born.

When the project began in 2018, two small piles of covered snow had melted by September during the state’s third-warmest summer since 1895. Undeterred, the experiment’s organizers decided to cover 45 times more snow this year and to make important changes in the design.

An insulating blanket designed to keep hardening concrete warm was discarded as the bottom layer; the wood chips remained; and a covering of white, permeable fabric replaced a sheet of plastic on top.

The shape of the mound also was altered to lessen runoff and the potential for cracking and snow slides.

“We’ve tried half a dozen different cover techniques,” Bierman said. The wood chips proved critical, he added. They absorb moisture, which then takes a great deal of energy to heat.

As a result, Craftsbury and UVM researchers retained most of the 9,300 cubic meters that they had set aside in spring. The experiment showed that over-summer storage could help in years when nature might not be as generous as this season, with its early snowfall.

“This has an impact on people’s lives,” Bierman said.


The experiment indicates that now, instead of hoping that November will turn cold enough to cover the trails with man-made snow, Craftsbury “can count on making reservations” in late fall, Bierman said.

“The long-term goal is to keep doing this so we can consistently open in mid-November,” said Geer, who like her husband is a former Olympic rower. “It's a critical time for us.”

Going forward, the economics of outdoor winter sports seems certain to face critical tests far beyond Craftsbury’s woods.

“We know climate change is happening. So, what are we going to do about it and protect this past of our heritage?” said Weiss, the UVM grad student, who is an ardent skier.

“You can’t just be a ski center anymore. And if you want to stay a ski center, snow storage might be an option,” she said.

What isn’t optional, the scientists said, is that Nordic skiing will be forced to adapt — quickly and significantly — if New England continues to warm.

“People will retreat up the mountains,” Bierman said of the skiers. “But you can only do it so high, and then we run out of mountains.”

Snow from last winter was saved over the summer for use on Nordic trails at the Craftsbury Outdoor Center.Caleb Kenna for The Boston Globe

Brian MacQuarrie can be reached at brian.macquarrie@globe.com.