Tyson Bradley, director of Utah Mountain Adventures, was with one of five ski parties on the mountain at the time of the accident and when he heard screams from below, he made the call for a Life Flight helicopter.
The reason for the crowd on what locals call "the Pfeiff," late in the season when snow quality can be marginal, is a classic example of an extreme ski descent, according to Bradley.
"The run normally requires a rappel," he said. "However, due to the unusually deep snow pack in our mountains this spring, the line is filled-in [so] it can be skied without a rope. This is one of those once-in-a-lifetime opportunities for us denizens of extreme skiing. We all wanted to experience skiing this great line in the rare conditions."
He said early reports of an avalanche in the area were wrong and that weather and snow conditions may have been to blame.
"We sort of expected better snow," said Bradley, 44. "The conditions were not as good as we hoped."
The six to eight inches of new snow had been flushed away by earlier skiers and the surface was a "hard bed" of snow and ice.
Both women were skilled climbers and skiers. Hall said she had skied 50 days this winter without a ski pass.
"Like a lot of people who live in the Rocky Mountains, they love to challenge themselves and they love the personal reward they get from climbing and sitting on top and skiing down," said Bradley. "It's an athletic challenge and it's about overcoming fear."
Back country skiing is a "huge growing sport," according to Bradley, who has led groups since 1994. "It's ski mountaineering and extreme skiing."
As for the Hall and Lund, he said they were "just really nice and cute and fun and athletic. We were all chatting with them at the top and we were having a fun day until all of a sudden things went sideways."
Hall said she wouldn't return to the mountain right away. "Well," she said with a laugh, "it's the end of the season."
"I am not going to say I will never ski back country again," she said. "It's one of my passions to be outside and mistakes happen. But we are both competent skiers and we know the risks were are taking."
ABC News' information specialist Brad Martin contributed to this story.