By Lindsey Konkel for The Daily Climate

PRINCETON, Mass. – When Aaron Sherritt took a job as a ski instructor at a hill near his parents' home to make some extra money during college break, he didn't think much about how the snow under his skis got there.

Fifteen years later, it's all he thinks about. 

As snowmaking supervisor at Wachusett Mountain, it's his job make sure the slopes are cloaked in white corduroy from late fall to early spring, even when Mother Nature won't cooperate.

"Snowmaking saves a bad year," said Sherritt. "It provides us a chance to operate when we might otherwise have to close."

The investment in manmade snow has brought stability – and profits – to an industry that once lived and died by Mother Nature's whims.

The predictability is vital for the economic health of a multi-billion dollar industry. But some fear snowmaking technology may not be able to overcome warming trends already unfolding.

"In some scenarios, it's not even a case of snowmaking technology. We just don't see it getting cold enough to make sufficient artificial snow," said Jordy Hendrikx, director of Montana State University's Snow and Avalanche Laboratory.

Protecting a 100-day season

Or wet enough.

Snowmaking requires cold, water and power. California ski resorts, suffering through the driest year in the state's recorded history, are missing out on the white stuff. The biggest resorts are only partially open; smaller ones have yet to open at all this season.  

But the industry's California woes could become commonplace. By 2039, only half of the 103 ski areas in the U.S. Northeast would be able to maintain a 100-day season, an industry benchmark for profitability, according to a study published last year. 

In Austria and Italy, ski resorts in the Tyrol region could ensure a 100-day ski season until the 2030s or 2040s only with 100 percent snowmaking cover and state-of-the-art equipment. Even then, many ski areas would lose the economically important Christmas holidays as early as the 2020s, according to researchers from Austria.

Rising temperatures and changing precipitation in the Southern Hemisphere would likely shorten Australia's ski season from today's average of 94 to 155 days to 81 to 114 days by the 2040s, Hendrikx and colleagues found. Australia's ski industry would be completely gone by the 2090s, their models predicted.

In Massachusetts, the typical season at Wachusett Mountain runs from late November or early December to late March or early April. They strive to open by Thanksgiving, though even with 300 snow guns, they don't always hit that mark. This year cold air came early: While there wasn't a trace of natural snow in the parking lot, opening day came a full week before Thanksgiving thanks to Sherritt and his 15-person team.

Holidays are the lifeblood of ski areas. In the Northeast, 15 percent to 20 percent of total skier visits for the year happen between Christmas and the New Year. While it's hard to say how much a bad snow year may hurt an individual resort's bottom line, "skier visits typically go down 10 to 15 percent in record warm winters while operating costs may go up," said Daniel Scott, a professor of tourism management at the University of Waterloo in Canada. 

Skiers descend a slope in front of a snow cannon in Val d'Isere, French Alps

Skiers descend a slope in front of a snow cannon, on December 12, 2012, in Val d'Isere, French Alps. (Photo: Phillippe Desmazes/AFP/Getty Images)

Half the energy budget

Manmade snow comes at a price. Resorts may spend 50 percent or more of their annual energy budget on snowmaking. 

And it's water-intensive, too. Snowmaking at Wachusett can draw up to 4,200 gallons of water per minute when the system is close to capacity, said Sherritt. That's an Olympic-sized swimming pool's worth of water every 2.5 hours.

Most ski areas find it worth the cost. The National Ski Areas Association, a Colorado-based trade group, reported that close to 90 percent of their 300 member resorts make at least some artificial snow. While there is no official estimate on how much the U.S. ski industry has invested in snowmaking, the price tag for New England's 100-plus ski areas alone is likely in the hundreds of millions of dollars, said Daniel Scott, professor of tourism management at the University of Waterloo in Canada.

In some ways, snowmaking has changed very little since its advent. It's still just two ingredients – water and pressurized air – forced through a nozzle. And it needs to be cold – 3 to 4 degrees below freezing, in most cases (snowmakers can stretch the range to just above freezing in extremely low humidity). What's changed is the amount of energy – and time – it takes to get snow.

"Fifteen years ago, it would take a week to make enough snow to open a trail. We can now make the same amount in 24 hours," said Sherritt. 

Precision science

The quest for energy efficiency and innovation has pushed snowmaking from a cottage industry to a precision science. Ski area operators began experimenting with artificial snow in the 1940s and 1950s. Legendary ski resort operator Walt Schoenknecht became the first to use it widely, making snow with a modified irrigation sprinkler at Connecticut's Mohawk Mountain in 1949.

Today, snowmaking has brought stability to the ski season, said Scott. Old-time skiers will remember much more variability in the 1970s and '80s, when resorts depended heavily on natural snow and cold temperatures. 

That stability has allowed the industry to flourish. But it has also given consumers less appetite for variability, Hendrikx said. "People now expect to ski at Christmas and may be less understanding of climate variability."

Snowmaking has also allowed for the proliferation of ski resorts in unlikely locations. Forty U.S. states, including Hawaii and Alabama, boast winter snow skiing. But can it last?

"In Southern California, we're 100 percent reliant on manmade snow," said Ben Smith, general manager at Mountain High Resort located in the San Gabriel Mountains, about an hour from Los Angeles. 

Even some of California's big mountain resorts, known for feet of fresh powder, are scaling up their snowmaking operations. Lake Tahoe's Squaw Valley Ski Resort, high in California's Sierra Nevada, records an average of 450 inches of natural snow each year. Yet two years ago, the resort spent $2.6 million on new snow guns and upgrades to snowmaking equipment.

"We see snowmaking as an insurance plan," said Melissa Brouse, a spokesperson for the resort. The snow guns are used mainly to create snow cover at lower elevations where snowfall totals may be less. 

A general view of the snow machines at the Halfpipe venue ahead of the Sochi 2014 Winter Olympics

A general view of the snow machines at the Halfpipe venue ahead of the Sochi 2014 Winter Olympics on Feb. 2, in Rosa Khutor, Sochi. (Photo: Julian Finney/Getty Images)

Unable to save the season

But even snow guns aren't saving Tahoe's season this year. The Sierra snowpack is 17 percent of normal this year – a record. Just one of 14 ski runs on Squaw Valley's upper mountain is open. Mammoth Mountain, normally blanketed in 400 inches of snow a year, logged only 3 inches last month until a storm dropped 12 much-needed inches of powder Jan. 30 and 31. Smaller ski areas, such as Badger Pass in Yosemite and Donner Ranch near Tahoe, have yet to open this season.

In drought-stressed regions, water scarcity may be a limiting factor in determining how much snowmaking can serve as an adaptation to climate change

Management of scarce water is a perennial issue in the high desert of northern Arizona. For 73 years of its 75-year history, Arizona Snowbowl, near Flagstaff, struggled solely on natural snowfall for its operations. "You don't take a precious resource like water in the desert and throw it on the ski hill. There were winters when we were only open for a couple dozen days," said Jason Stratton, a Snowbowl spokesman.

In 2012, Snowbowl won approval to make snow from reclaimed wastewater, after a legal dispute with Native American tribes that the wastewater runoff would defile nearby sacred sites. "Snowmaking is a must for us to continue to exist. It gives us a future," said Stratton. 

In Massachusetts where the water is more plentiful, Sherritt's main concern is getting enough snow on the ground early in the season and making sure there is enough to last late into March. He's not thinking too much about climate change.

"I guess we're along for the ride. If it doesn't get cold enough to make snow, there's not much we can do. I can't change physics," he said.

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This story was originally written for The Daily Climate and was republished with permission here.