By Max Klinger, New York Times

TRUCKEE — The snowboarder Jeremy Jones arrived at the Atomfjella Mountains on Svalbard, an island above the Arctic Circle, after 30 hours of tundra crossing on a rattling snowmobile convoy in April 2011. He had invited Terje Haakonsen, known in the snowboarding world for his ability to ride almost anything, any style, to attempt the summit and first descent of a set of precipitously icy couloirs.

Jones, 38, spends years scouting locations and assessing risks. “He walks away from stuff all the time,” his brother Steve said. “He’s incredibly patient.”

Jeremy Jones of Truckee is making snowboard history. Photo/New York Times

As the men arrived at midnight to get their first look at the steep chutes they would be climbing, the skies were still filled with endless sunlight, and something occurred to Jones that he had not anticipated, despite years of diligent planning.

“Man, I hope Terje’s even up for this,” he thought, signaling just how daring his snowboarding exploits had become.

Haakonsen grew up a three-hour flight from Svalbard but never knew it held mountains as impressive as the Atomfjella. “My first reaction was ‘Wow,’” he said.

He eventually accepted the challenge, riding his lines with his usual brio, but said that hiking up those sheer walls had gripped him more than he could remember.

The same might be said about many of the partners Jones invites on his backcountry adventures, because for the past few years, he has committed himself to summits and descents around the world that are groundbreaking in size, scope and degree of vertical exposure.

“He’s pushing technical snowboarding, meaning very critical turns on really steep terrain, and executing like no one else,” said Lucas Debari, another expedition partner and a freeriding standout from the state of Washington. “Other guys are going bigger off cliffs, or going faster, but no one is pushing technical snowboarding on lines of consequence like he is.”

The precedence of these feats is largely the product of Jones’s unconventional methods, which incorporate splitboarding, mountaineering techniques and multiweek approaches, and have allowed him to access mountain ranges and massifs that were previously considered untouchable, if charted at all.

At a local restaurant here in his hometown, Jones does not look like one of the world’s most radical snowboarders. A 38-year-old father of two, he is soft-spoken and friendly, an outlier in a sport known more for brazenness than modesty. But for more than two decades, as snowboarders have started trends and realized Olympic ambitions, Jones has pursued a singular dream: riding some of the biggest, significant mountains in the world.

Over a veggie burger stacked with bacon, he traced his evolution from an Alpine racer from Cape Cod, Mass., to an elder statesman of snowboarding in Lake Tahoe. Jones followed his two older brothers to Jackson, Wyo., when he was 16. Soon after, he took his first trip to Alaska, where, he said, he lived in his car for months.

Jones met his wife, Tiffany, a former competitive snowboarder, in Lake Tahoe. She knows the risks and long absences associated with the profession.

“I watch all his movies,” she said in a telephone interview, “and if he does something unnecessarily dangerous, I’ll call him on it. But he’s a very calm person, not ego-driven, and he always has a thought process for every decision, and he can always walk me through it.”

Jones’s position on snowboarding’s hierarchy is hard to calibrate if only because he nearly predates the sport. In the 1990s, he began pushing big-mountain freeriding and exploring Alaska’s varied and challenging terrain by helicopter. This year, he was voted Snowboarder magazine’s big-mountain rider of the year for the 10th time.

Jim Zellers, a snowboarding pioneer in Alaska in the 1980s, recalled the first time he met Jones, in Squaw Valley, in the mid-1990s.

“I was following him down this really steep, technical line, and I remember thinking, ‘This guy is special,’” Zellers said. “To this day, there’s no one who looks at the landform, the geomorphology, like him and thinks about what would be the most interesting part of the mountain to be involved in.”

But at a certain point, Jones felt limited by the helicopter exploration as it became as popular and predictable as resort riding.

“It’d be the best day of the year,” he said, “and I’m standing on top of the best line in the best heli zone in the world, and I realize that I’m riding it for the third time and it’s already been in multiple movies and magazines. Where’s the progression or adventure in that?”

He added: “You eventually discover that with a heli and snowmobile, you can only access about 5 percent of the mountain range. To keep the adventure alive, we had to turn to something else.”

He turned to the splitboard, a snowboard that separates into two touring skis, which allowed him a new way to get around the backcountry and ascend mountains. The splitboard had been around since the 1980s in Europe, but the crude initial designs never caught on. As Jones began approaching these mountains from the bottom, he also began borrowing equipment from traditional Alpinism like ice axes, crampons and climbing ropes.

Conrad Anker, a leading mountaineer, climber and skier from Montana, compared Jones’s feats to the rock climber Alex Honnold’s free climbing.

“It’s really high stakes, the hardest level of technicality and difficulty,” Anker said. “You take that human-power element and the solid mountaineering, and you see why he’s so well-respected in the mountaineering community.”

In many cases, this self-ascent ethos has allowed Jones to outperform helicopters in traveling deeper into mountain ranges, waiting out bad weather and finding steeper lines to ride. As he approached these mountains from below, his knowledge of snow and avalanche conditions grew, and his understanding of a mountain’s features expanded the types of lines he was willing to attempt.

After failing to persuade his longtime sponsor, Rossignol, and several other companies to produce a splitboard for him, he started making his own. Then in 2010, Teton Gravity Research, his brothers’ production company, released the first of a planned trilogy of backcountry snowboarding movies, “Deeper,” which in Jones’s words “threw a bunch of gas on the backcountry fire that had been developing for years.”

Despite a decline in overall sales of snowboards, splitboarding has become the fastest-growing segment in the sport, rising about 32 percent so far this season compared with the same period last season. (Three companies that refused to make Jones a splitboard are now producing them.) One effect has been to move snowboarding from the resorts to the off piste, where the sport was conceived.

But with freedom comes risk. In the winter of 2010-11, 16 skiers or snowboarders died as a result of backcountry avalanches in the United States, according to the American Avalanche Association. During 2011-12, the number of deaths climbed to 20, as advancements in equipment made backcountry riding more accessible.

“You look at Europe and what the standard is for a technical mountaineering background for their winter athletes; it far surpasses the United States,” Anker said. “I see it all the time: seasoned skiers who get themselves into these avalanche situations, making preventable and sometimes fatal mistakes.”

Even Jones’s expeditions have had close calls. During the filming of “Further,” released in September as the second part in the trilogy, the snowboarder Forrest Shearer was knocked off balance by a batch of slough — a small surface-level slide — near the top of a steep, narrow chute in Japan and fell 1,200 feet before he recovered. In Austria, the husband-and-wife team Mitch Tölderer and Bibi Pekarek were feet from the summit of a giant peak when a slab they were standing on broke and slid. In each case, the riders were largely unscathed.

Jones tries to avoid these pitfalls with methodical research and planning.

“A lot of climbing has to do with ethics, and the style and manner in which you do things, in which you make decisions,” said Debari, the standout freerider. “He definitely brings that mind-set into snowboarding.”

Jones spends years scouting locations, gathering data on weather and snow, and talking to local guides before he selects a destination. On the mountain, the talk revolves around “slough management” and limiting “secondary exposure,” meaning avoiding areas that put his fall line above dangerous obstacles like cliffs, rocks, trees or gullies.

“He walks away from stuff all the time,” said Steve Jones, Jeremy’s oldest brother and longtime expedition partner, and a principal in Teton Gravity Research. “He’s incredibly patient, and that’s a big part of the unspoken trust that our family puts into what he does.”

Jones has learned to look for ranges where the predominant weather has a heavy maritime influence, generally meaning heavier snow that is less likely to form layers that can fracture and slide. He also searches for mountains that rise out of large, flat glaciers and ice fields, creating shallow avalanche run-outs instead of deep, obstacle-filled terrain traps.

In perhaps his most risky expedition, Jones traveled to the Wrangell-St. Elias Mountains in southeast Alaska. They sit in America’s largest and least explored national park, a mountainous zone larger than Switzerland. These ranges have achieved a high profile among climbers, skiers and snowboarders who consider them the tallest in the world, not in altitude, but in the sheer vertical relief with which they rise from flat ground.

In an email, the veteran Alaskan bush pilot Paul Claus wrote, “The St. Elias also have probably the hardest conditions found anywhere: the coldest temps, very bad weather, unfathomable amounts of snow and extreme remoteness.”

Jones had avoided the Wrangells after a friend, Aaron Martin, disappeared in 2002 while skiing down a mountain there. After years of tracking the Wrangells’ weather, he thought it was time to go last April.

Jones planned to fly to Bagley Ice Field and set up camp for a month to get to know the weather, the snowpack and the best lines. He invited his longtime riding partner Ryland Bell and Debari.

They discovered some of the most complex and technical walls, spines and couloirs they had ever seen. But at the base of most of the walls were bergschrunds — gaping, 40-foot-deep crevasses. Everything they were going to ride had extreme secondary exposure, so one slip could be fatal.

“We’re talking about things that most people wouldn’t even consider being on,” Claus said. “Even if you were actually climbing the mountain with the goal of getting to the summit, you would not go where he went.”

Nonetheless, Jones, Bell and Debari tackled five major first descents, with names like the Tooth and West Wall, in 30 days. After pushing his partners to their limits, Jones said he had one final goal: a “cherry line” in the middle of a “no man’s land” peak. He named it Space Needle, and hiked there alone at 7pm, carving a gutsy 1,400-foot line on one of the trip’s nonpareil descents.

“The pitch of what he was riding — that was incomprehensible,”Debari said. “Not just steep and technical, but mentally so challenging. You have to be the most calculated snowboarder in the world to do what he does over and over again and survive.”

Even at 38, Jones says he has no plans to slow down.

“It’s funny,” he said. “With splitboarding, I have less pain than I’ve ever had. I spend more of my day hiking and getting a good full-body workout, and less time on high-impact descents.”

When asked about his next movie and his plans to top his previous feats, he turned philosophical, saying, “In 12 hours, we go out and experience nearly every emotion in the human range: physical strain, frustration, pain, anxiety, fear, calculation, the joy of making it to the top, the beauty of your surroundings, camaraderie, then the 60 seconds of adrenaline-filled activity.”

He added: “If it was all about the adrenaline and the descent, you wouldn’t last doing the style of riding I do. It’s about a much wider experience. But, yes, we’ve got some pretty amazing stuff planned.”