The rental ski boots are still lined up neatly on a shelf, next to a clutter of skis. But after 17 years in operation, the cross-country ski center at Morse Farm Maple Sugarworks in Montpelier won't open this winter.

It's not for lack of customers. Plenty of skiers want to glide along the center's 14-kilometer groomed Nordic ski trail through woods, up hills and over flat pasture.

The problem is climatic, and proprietor Burr Morse attributes it to global warming. "We get a week or two of groomable snow, and then it goes away," he explained. "And these days, the January thaw seems to last two or three weeks."

Such unfavorable conditions weren't always the case, according to Morse, who is 70. When he was growing up on the farm, there was so much natural snow that the adults had to shovel the barn roof several times each winter so the structure wouldn't collapse. Abundant natural drifts covered a small hill where the family rigged up a rope tow for downhill skiing in the 1960s. Workers donned snowshoes in winter to maintain the taps on the maples.

Now the barn roof rarely needs to be shoveled. The rope tow is long gone. And snowshoes aren't a necessity in the sugarbush — the drifts don't get very deep, Morse said.

"I think we've kind of transitioned from a snow belt to an ice belt," he said.

Vermont has more than 30 Nordic ski areas. Increasingly, they face a tough weather challenge, especially when situated at lower elevations, as Morse is. Located three miles north of downtown Montpelier, the property sits at about 1,200 feet.

Higher elevations benefit Nordic areas such as the Trapp Family Lodge ski center in Stowe and the Rikert Nordic Center, Middlebury College's touring center in Ripton.

But those two areas and a few others, such as the Craftsbury Outdoor Center, have a more targeted tool: artificial snowmaking — something the low-budget Morse center can't afford.

To make snow on a one-kilometer loop would cost $70,000 to $100,000, explained Chip Stone, one of the center's founders, as he stood next to an idle snow groomer last week. "This is an operation where we have an end-of-the-year celebration if we break even."

Soon snowmaking could be just as essential to Vermont's Nordic ski centers as it is to the state's downhill areas, according to Adam White, director of communications at Ski Vermont, a trade association that represents 50 alpine and Nordic areas in the state.

Even some small areas are making the investment, he noted.

Huntington's family-run Sleepy Hollow Inn, Ski and Bike Center installed snowmaking in 2012 and recently added capacity for a total investment of about $140,000. Skier visits have since increased from 5,200 to 6,200 annually. This year, the snow guns guarantee at least two kilometers will be snow-covered, said general manager Eli Enman.

That's in contrast to its neighbor a few miles up the road.

"We have never thought that it would pay to invest in snowmaking," said Dave Brautigam, president of the Camel's Hump Nordic Ski Area. The nonprofit attracts about 100 season pass holders each winter and is mostly a labor of love.

Brautigam and his wife, Myra Handy, carved out the first trails on her parents' hill farm in the late 1970s. The network gradually expanded to property inside Camel's Hump State Park.

Today, volunteers help maintain 65 kilometers of groomed and backcountry terrain that stretches from about 1,400 feet, where the snow is patchy, to 2,200 feet, where the drifts are often a few feet deep. What lures skiers back year after year? New trails at higher elevations. "That's our way of surviving," Brautigam said.

The Craftsbury Outdoor Center, which started making the white stuff in 2011, is experimenting with another strategy: snow storage — stockpiling large mounds of snow and attempting to preserve it over the summer.

At the end of last winter, workers piled two garage-size mounds of natural and artificial snow and covered them with a thick layer of wood chips. A University of Vermont team, including geology professor Paul Bierman, studied the piles — one in shady woods and one in a higher-elevation meadow — to see how wind and sun affected the melt rate. A small load of snow was removed for a sledding party at the Craftsbury Fourth of July celebration. Otherwise, the snow was left to do its thing.

By September, both piles were mostly puddles under the wood chips — but the one in the woods lasted longer. This winter, Craftsbury Outdoor Center hopes to build a pile 35 times larger in the woodsy spot in an effort to use the summer storage technique for real. Bierman believes the method could hold promise for the region. "If we can test it here and make it work, it may be a way for other Nordic centers to buffer the impact of climate change," he said.

Vermont didn't invent snow storage, but the practice could work here to help some small ski areas, said John Morton, a Thetford-based Nordic trail designer and former Nordic coach at Dartmouth College.

He believes global warming is "absolutely" having an impact on the snowpack and the sport, adding that it takes just a few degrees to mess up Mother Nature's snowmaking potential.

"These storms that used to dump two feet or three feet of snow on the mountains of Vermont and New Hampshire are now starting as rain, then maybe dumping six inches of wet, heavy snow and then ending up with another couple hours of rain," Morton said. "That makes a huge difference to the quality of the Nordic skiing in this part of the country."

At the 500-acre Catamount Outdoor Family Center in Williston, operations manager Tag Carpenter knows that all too well. Natural snow cover on the center's 35 kilometers of trails has diminished significantly over the last few decades, said Carpenter. He believes it's too warm at the property to make snow.

"You need sustained temperatures below freezing, and that doesn't happen at 800 feet, where we happen to be located," he said.

Instead, the outdoor center has diversified, with fat-tire biking in the winter and a full roster of year-round activities, from foot races to cyclo-cross competitions. Later this year, the Town of Williston will purchase the property from longtime owners Jim and Lucy McCullough in a $1.2 million conservation deal funded by town, state, federal and private money. The center will continue to operate as it has, and there is no expectation that Nordic skiing will be much of a revenue booster going forward, Carpenter said. "From a mental standpoint and a budgetary standpoint, we're kind of poised to say, 'Let's expect a very limited winter season, and if we get more than that, it's a bonus,'" he said.

Vermont's winters are growing shorter, according to the Vermont Climate Assessment, a 2014 UVM study. Since 1960, the state's average temperature has increased by 1.3 degrees Fahrenheit, the study shows. The state's freeze-thaw cycle is also changing, with the first freeze arriving later in the fall and the first thaw earlier in the spring. Over the past 40 years, the freeze period declined by 3.9 days per decade, according to the study. That trend is expected to continue.

Most scientists worldwide believe humans are causing global warming. While the rate of change is debated, some observers say there's no denying the shrinking piles of snow.

Morse is among them. The cross-country operation was conceived as a sideline to his thriving maple syrup operation, which ships all over the country and attracts busloads of tourists. Last Thursday, visitors bought maple candy and bottles of syrup on a gray November day that spit drops of rain — not snow — over the woods and farm fields.

When friends and neighbors suggested establishing a ski trail network back in 2001, it seemed like a good idea. So Morse joined four partners to invest in trail making and equipment. The center hosted high school races and served cocoa at tables in the retail store.

Now Morse is ready to pass the baton. And at least one person is extending a hand.

The owner of Cabot Smith Farm 20 miles to the north says he's "80 percent" sure he wants to buy Morse's trail groomer and ski equipment to start his own Nordic center. Richard Hourihan purchased the 265-acre property in Cabot 18 years ago and sells strawberries in summer, squash in fall and Christmas trees during the holidays. Then there's a lull until spring. "We do nothing. So we're gonna do that," Hourihan said. "We're going to have cross-country skiing and possibly fat-tire biking.''

The property sits on a ridge overlooking Cabot village with views of Mount Mansfield in the distance. Old stone walls border the fields. Last Thursday afternoon, farmworkers spread straw over rows of strawberry plants, and Hourihan took Christmas tree orders over the phone.

The bottom of the farm sits at 1,400 feet, and the highest point reaches 2,200 feet. One hundred inches of snow fell last year — twice what Morse got, according to Hourihan. The drifts lasted well into April. "The stuff doesn't go anywhere. It just stays," said Hourihan.

He's drafted a letter to Morse's customers pitching the idea of a Nordic center on his farm. Based in part on their feedback, Hourihan says he will decide in the next few weeks whether to proceed. If he does, he would open this winter and gradually build the operation.

"I don't expect to be Trapps or Craftsbury or Bolton," he said. "If I had 10 people a day, I'd be happy. I'd be ecstatic."

He insists Mother Nature won't need any help on his property.

"It will start any time now," Hourihan said. "It will start snowing."