AFTER THEIR legendary races were over, the Skiing Legends of Utah assembled in front of a banner for a legendary group picture. This was a once in a lifetime photo opportunity. Or once in many lifetimes. The producer from Channel 4, Salt Lake City's ABC affiliate, suggested that this might even be a mo ment "Good Morning America" would savor for an opening intro.

On cue, the 28 Skiing Legends said: "From Alta's 50th Birthday Party - Good Morning America!"Watch for it one of these cold winter mornings.

The Legends, incidentally, pronounced "Alta" properly. As in "Al-ta." Not "All-ta," as it is commonly said by people from Wisconsin and Michigan and California and other foreign places who make their trek to skiing's mecca and then blow their cover by butchering the name.

Wednesday's Legends Ski Race was the first of many fetes planned during 1989 to commemorate Alta's 50th birthday.

It was 50 years ago this March that the forerunner of today's Collins Lift started carrying skiers up the mountain for 15 cents a ride.

Every year since, there has been concern about enough snow for Thanksgiving. Before that, no one much cared.

The Legends race took place, appropriately, almost directly below the Collins Lift, on the lower (flat) portion of Nina's Curve - the famous run that has hosted any number of Snow Cups and other not-able races over the past half-century. (It was also, no doubt, down Nina's Curve that the original Alta Ski Company customer pointed his wooden skis and beartrap bindings downhill and got his 15 cents' worth, although it wasn't known as Nina's Curve at the time).

Any number of famous Utah-raised or Utah-adopted skiers were among Wednesday's legendary racers. Several U.S. Olympic teams were represented, not to mention a couple of Norwegian Olympic teams (in the fine form of Stein Eriksen), as well as dozens of University of Utah NCAA championship teams.

Jim Gaddis, the 1962 U.S. giant slalom champion, was one of the Legends who was there. Gaddis once won three Alta Snow Cups in a row, in 1962, 1963 and 1964 - a period of time when he owned Nina's Curve.

Gaddis remembered the first time he ever saw Alta, as a 9-year-old.

"My brother drove me up (from Salt Lake) and dropped me off up on the highway," he said. "I just walked over the snowbank to get to the hill, instead of going down the ramp. I immediately sunk in over my head. It took me 15 minutes to get out.

"That's my first memory of Alta. All that snow . . . and wondering if I'd ever get out of it."

It was all downhill after that. Gaddis went on to form a love affair with the area, as did other budding Legends. Like, for instance, Margo Walters, who is now Margo Walters McDonald, and who was another of those on hand yesterday to pay her return respects to Nina's Curve.

Margo won three or four Snow Cups there herself - she can't remember the exact number. She knows she won in 1961, 1962 and 1963, and she knows she didn't win in 1964. That was the year she was on the U.S. Olympic Team and her pursuits were elsewhere.

She remembered coming to Alta as a teen-ager, with a number of other kids who loved to ski race, but were not organized into a team. They would practice on a hill across from the lifts.

"We had the best coaches in the world," Margo said. "The instructors at Alta would come by and they were so generous and so willing. Alf Engen, and Marv Melville, and Keith Lange, and people like that. They'd ski with us all day long, coaching us, setting gates. For nothing."

Alf Engen and Marv Melville were also among the Legends who raced Wednesday.

Engen, the Alta Ski School director who has been around as long as the Collins Lift, was declared the unofficial winner of the races. His time down the course wasn't the fastest, but after a sophisticated and civilized handicapping formula was adapted, he beat everybody else by about 80 years, which is how old he'll be this year even if neither he nor anyone else can believe it.

But, then, no one can believe Alta is turning 50 either . . . Or that all those Legends were once 9-year-olds trying to climb out of snow drifts . . . Or that a lift ride up Collins used to cost 15 cents.