Call Him Viking Voyager : Olympics: For Vegard Ulvang, winning skiing medals is only the beginning of the adventure.

And for his next trick, Vegard the Viking will sky-dive from a biplane onto the back of a dog sled, which he will mush to a triumphant victory in Alaska’s Iditarod.

Then he will swim the Bering Strait, ski across Siberia to his home in Kirkenes in the far north of Norway, where he will go bear hunting with a switch. And in the afternoon. . . .

These days, when the talk gets around to adventuring, Vegard the Viking’s is one of the first names that pops up.

In his professional life, he is Vegard Ulvang--that’s WAY-guard OOL-wahng , which doesn’t have quite the ring of Vegard the Viking--one of the stars of the star-studded Norwegian cross-country ski racing team, winner of four medals two years ago in the Albertville Games, three golds and a silver, and former winner of the World Cup title.

In his spare time, the world is his playground. He climbs mountains. He treks across forbidding terrain in areas best known to the nomads who live there. He skis where only other adventurers--or perhaps none--have skied before. He has tried sky-diving. And if he said he was going to run with the bulls at Pamplona, no one would be surprised. He probably would wind up chasing them .

So what’s with this guy? Isn’t it enough, at 30, to be one of the world’s great athletes, a national hero in a ski-crazy country who earns nearly $1 million annually on his skinny slats? Can’t he simply bask in the adulation and spend his time off playing at Monte Carlo? Must he attempt these offbeat ventures? This skiing across Greenland? This climbing of four mountains on four continents in a five-week period? This trekking across Mongolia? This canoeing in the wilds of Siberia?

He must.

“I like challenges,” Ulvang said the other day from Davos, Switzerland, where he and his Norwegian teammates were concluding high-altitude training for the Lillehammer Winter Olympics, in which he hopes to win more gold.

“I do (adventuring) because I like it. It’s not so dangerous. People only think it is dangerous because the media says so. But these things, many I have been doing all my life. I was born with a close contact with nature, so it is not unusual for me.

“Besides, it is good always to have a goal. And it is all good preparation for life as a skier. It is a way to stay in training without training.”

Not dangerous, he says:

--In the summer of 1990, on the way down from Denali, the former Mt. McKinley in Alaska, Ulvang’s brother and adventuring companion, Ketil, went through the ice of Wonder Lake, and eventually, in trying to pull him out, so did Ulvang and Frenchman Pierre Gay-Perret, their mountain-climbing mentor.

Ulvang got out, pulled the others out, then stayed with the nearly unconscious Ketil while Gay-Perret ran for help. Park rangers later lifted Ketil out by helicopter.

--In the summer of 1991, Ulvang and Gay-Perret decided to ski across Greenland, following the 350-mile route used by Norwegian polar explorer Fridtjof Nansen on a six-week journey in 1888. With their modern equipment, they figured, it would take 20 days, and they packed 20 days’ worth of food.

Storms early in the trip left them far behind schedule, however, and short of supplies, if they were to stick to their schedule. Instead, they went on short rations and picked up the pace, finishing the trip in 14 days and, in Ulvang’s case, 25 pounds lighter.

--The summer after his Albertville triumph, he and a group of other Norwegians went on their climbing spree. He conquered Mt. Elbrus on the Russian-Georgian border, Mt. Kilimanjaro in Tanzania, Mt. Puncak Jaya in New Guinea, and nearly conquered Mt. Aconcagua in Argentina before being turned back by bad weather.

When the group reached 16,600 feet, Ulvang and another climber were chosen for the assault on the the 22,834-foot summit. The other climber turned back at 19,000 feet, fearing he had frozen his toes, and Ulvang continued alone. He reached 22,000 feet, then a storm hit and the wind threatened to blow him off the mountain. Fearing an avalanche, he too turned back.

--Last summer, Ulvang, Gay-Perret and Vladimir Smirnov, a former Soviet cross-country skiing star who now represents his native Kazakhstan, trekked across Mongolia.

Along the way, their Mongolian guide disappeared. Suspecting foul play, Mongolian authorities told the adventurers nobody could leave until it was learned what had become of the guide. He turned up four days later, trying to cross the border into Russia.

And those are only the narrow escapes Ulvang has told us about.

Even when he isn’t particularly looking for trouble, Ulvang sometimes finds it. He spent two days last fall in Sarajevo, the 1984 Winter Olympic city turned battleground, representing an Olympic relief organization. Driving through town, he and his group came under sniper fire.

Mt. Everest was to have been this summer’s adventure, and it still may be. First, though, Ulvang has a grim bit of family business to attend to.

Ketil, a physical therapist, dropped out of sight last October not far from Kirkenes, about 250 miles north of the Arctic Circle, and hasn’t been seen since. Returning home one evening with a group of other physical therapists from a professional engagement, Ketil, 32, got out of the car, saying he would run the rest of the way through the woods. He had run in those woods all his life, and the 17-mile distance figured to be about a two-hour workout for him.

He never arrived home.

Vegard, training in the Italian Alps, quickly flew home to help in the subsequent search, said to be one of the most intensive in Norwegian history. Mounting snow, however, thwarted searchers, dogs and high-tech tracing devices. Tracks that might not even have been Ketil’s were inconclusive and quickly disappeared.

So Ulvang’s first order of business, he said, when spring comes to Kirkenes and the snow has melted, will be to find his brother’s body.

“I will look for him until I find him,” he said.

Until then, there is nothing he can do, so he does what he always does in the winter. He trains for skiing and he skis. “It was a tragedy for me and my family, but I try to think of him in a positive way, as an inspiration for the Olympics,” Ulvang said. “I think that would have been his wish.”

In the two years since Albertville, Ulvang’s star has dimmed a bit, and Bjorn Daehli, who also won three golds and a silver in the ’92 Games, has become the dominant Norwegian. Still, Ulvang figures he is as ready as he can be, that gold is not out of the question for him.

“I still love skiing,” he said. “The most interesting challenge still is pushing my body. The last week has been a little bit boring because we’ve been winding down our hard training, skiing hard in the morning, then relaxing. I love to go skiing--I’ve skied all my life--and if I ski well, I still can win.”

There figure to be as many as 100,000 home-grown fans for any given cross-country event--Norwegian fans overwhelmed Albertville--and they will surely celebrate if Daehlie wins some races, as anticipated.

And if Vegard the Viking turns in a surprise, the din will be heard from here to Kirkenes.