Averell Harriman had a problem. Count Felix Schaffgotsch came up with a big solution.

The year was 1936. The great North American railroads were competing for passenger traffic as zealously as the airlines are battling today. Harriman, the young chairman of the Union Pacific, had a sleek set of crack trains running between Chicago and the West Coast. Unfortunately, there weren't many destinations along the Union Pacific route where large numbers of passengers wanted to go.

To the south, the Santa Fe was hauling people by the thousands to its railhead at the Grand Canyon. Up north, the Canadian Pacific offered the lure of Banff and Lake Louise. The Union Pacific had no such magnet along its tracks.

But Harriman had an idea. He knew that the great European railroads did a brisk business each winter hauling skiers to remote resort areas like St. Moritz. So Harriman dispatched a young Austrian skier, Count Felix Schaffgotsch, to find a setting for an American St. Moritz.

The count loaded his baggage and five pairs of wooden skis into the Union Pacific's "City of Los Angeles" and set off on a mountain hunt. After prowling for weeks through the northern Rockies, he sent back an urgent wire: He had found the perfect spot on a scenic, sunny mountainside near the Union Pacific depot at the tiny mining town of Ketchum, Idaho.

And so was born, 50 years ago this winter, the famous resort that Harriman named "Sun Valley." It was the first destination ski resort in the United States and the home of many other skiing firsts, including the world's first chairlift and the first "package deal" for visiting skiers (as late as 1950, it cost just $75 for a week's lodging, lessons and lift tickets).

Thus it is not too outrageous a stretch to say that American skiing was born on this Idaho mountainside in the winter of 1936. That's what they say in Sun Valley, anyway, and that's why this season at the big resort in Sawtooth National Forest is being treated as one long celebration: "America's 50th Ski Birthday."

The Sun Valley Co. (no longer owned by the Union Pacific, which sold out in 1964) and the editors of Ski magazine, which published its first issue during that 1936 season, have scheduled all manner of hoopla for the current season, which runs through May 4. For the skiing vacationer, this birthday party might constitute good reason to make the trek to the Idaho mountains. But then, even in an ordinary year Sun Valley offers two good reasons for the trip: a charming western setting and a marvelous ski mountain.

"Sun Valley" today is a collective term for three distinct settlements in the rustic Wood River Valley. There's Sun Valley village, with the opulent lodge the Union Pacific engineers erected in a matter of weeks in 1936. A mile down the road is the little town of Ketchum, quaint by day and quite lively each night after the lifts close. Another mile away are some sprawling new condo developments at the base of the ski lifts.

Within the complex are two ski areas. Dollar Mountain, the site of that first chairlift, is a broad, gentle slope used now almost exclusively for beginners and young children. Bald Mountain, or "Baldy," is a major-league ski hill offering 50-plus trails and a vast spread of steep, open bowls served by a network of 12 chairlifts.

This clear distinction between beginner and experienced areas makes life easier for skiers of both persuasions.

A reader poll taken last year by Ski magazine rated Sun Valley's Bald Mountain the best ski area in the United States (Aspen was second, Vail was third). Those surveyed liked the steep runs and heavy powder Sun Valley offers, and they raved about the lack of traffic on the slopes and the absence of lines at the lifts.

There's lots of snow at Sun Valley; the powder is somewhat wetter, and heavier, than a skier might find in Colorado or Utah. There's much, much more of it than you'll ever see at Killington or Stowe.

The ski area is set in a ruggedly beautiful forest, and the view from the top of the upper lifts is unforgettable: The jagged, snow-capped peaks of the Sawtooth Range jut up through wisps of cloud into a deep blue sky, and the Wood River Valley stretches out southward toward the distant horizon. You could almost spend the day at the top of the hill soaking in this marvelous portrait of Mother Nature's handiwork.

Once you start down, things get tough. Sun Valley's Bald Mountain is a demanding place to ski; the "beginner" trails here would pass for advanced runs at places like Wisp or Roundtop. Sun Valley's expert runs are genuinely for experts; we somehow stumbled onto an innocent-sounding run called "Fire Trail" that seemed to head straight down into a forest that grew thicker and thicker as we sped faster and faster into it.

The real glory of Sun Valley, though, is found in the great natural bowls filled with thick powder snow glistening in the morning sun. These big open patches looming over the town of Ketchum first caught the eye and captured the imagination of Count Felix Schaffgotsch. In an oral history interview with the Ketchum Community Library, Harriman recalled the message he received from the young Austrian on a February morning in 1936, urging him to visit Ketchum and examine Bald Mountain as a potential resort site.

"So I got into a private railroad car . . . and we came out here," Harriman said. "I remember vividly getting out of the car in Ketchum. I put on my skis and skied into . . . this powder snow . . . There were all the mountains with gold in the background and the hills covered with snow. I fell in love with the place then and there."

Harriman immediately bought a 4,000-acre sheep ranch to be the site of the new resort, and placed a call to the table at the Stork Club in New York that was the hangout of legendary press agent Steve Hannagan.

Hannagan's contribution to the resort's mystique was enormous. It was the press agent who brushed aside the geographic name "Ketchum" and dubbed the spot "Sun Valley" -- a name he had originally dreamed up for a real estate development in Florida. Hannagan persuaded the Union Pacific moguls to add attractions for nonskiers: the skating rink, the luxurious dining rooms, the opera house and the heated outdoor pool.

Hannagan used his extensive Hollywood connections to give Sun Valley a celebrity aura; the movie colony made this remote patch of Idaho its favorite Christmas getaway. That, in turn, captured the attention of a nation that had previously considered skiing to be the pastime of a few hardy woodsmen in the snowy back country of New England and the upper Midwest.

Today, along the halls of the Sun Valley Lodge and in all the restaurants, ski shops and warming houses, there are countless reminders of those glory days: big black-and-white photos of Gary Cooper, Clark Gable, Marilyn Monroe, Groucho Marx and their ilk gamboling on the slopes. Every afternoon at 5 the Sun Valley Opera House shows Hollywood's grand tribute to the resort, "Sun Valley Serenade," starring Sonja Henie, Milton Berle and the Glenn Miller Orchestra.

All these features, plus the lovely old lodge and the delightful art-deco snow sculptures one sees everywhere, provide an aura of history and glamor that is a key part of the Sun Valley experience.

But the place has carried this celebrity fascination to the point of wretched excess. It seems like every time you turn the corner there's a marker noting that some Kennedy or other or one of Ernest Hemingway's wives once stood on the spot. And the current wave of "celebrity ski races" at Sun Valley includes a lot of "celebrities" known only to the most devoted teeny-bopper fan of the latest television sit-coms.

The fact is, Sun Valley has no need to sell celebrity. It has an endlessly interesting ski hill and a big range of motels, hotels and condominiums to stay in.

For all the gilt-edged history, prices here seem a little lower than at some other big western ski resorts like Vail or Park City. Two-bedroom condo units rent for about $125 per night, and you can get a double room at the town's best address, the Sun Valley Lodge, for less than that.

Lift tickets cost $27 for adults and $18 for children at Bald Mountain, and $18/$12 at Dollar, the beginner slope. Prices at the bars and shops seemed to us a little lower than comparable spots at other resorts.sw sk

Getting to Sun Valley is probably harder than it was in the era of the great passenger trains. You can fly to Boise or Salt Lake City and connect, via a small prop plane, to the airport at Hailey, Idaho, 12 miles from the resort. You can drive or take a bus from Boise (three hours) or Twin Falls, Idaho (1 1/2 hours).

Either way, it's a long trip. In fact, the one thing Sun Valley really needs today is the thing that got it started in the first place: a crack passenger train delivering skiers right to the door of Averell Harriman's winter playground.