Souza was attempting to become the first Olympic gymnast to compete in the Winter Olympics, and would have learned Wednesday if she had a spot to compete in freestyle skiing in Sochi.
Hers was the third critical injury suffered by an elite athlete in Utah in the past four years.
Pioneering freeskier Sarah Burke of Canada died in 2012 as a result injuries suffered in a crash in the halfpipe at the Park City Mountain Resort, the same place snowboarder Kevin Pearce was critically injured in 2009 before recovering.
It was not clear exactly where Souza was skiing in Park City when she was hurt, but a spokesman for Brazil's winter sports federation told the Bloomberg news agency that she crashed into a tree.
Souza was training to compete in aerials, the discipline in which athletes flip and spin high in the air after leaping off a jump.
She had taken up the sport only in July, according to Bloomberg, after she and training partner Joselane Rodrigues dos Santos were chosen following a trial in which Canadian coach Ryan Snow tested hopefuls on a trampoline. To that point, Souza had seen snow only once, during a trip to the Ukraine for a gymnastics competition.
Snow was with Souza when the accident occurred, the BOC said.
The committee said Souza was wearing a helmet when her accident occurred, as she skied "freely" alongside Snow. It provided no other details on the accident.
The committee expected to confirm Wednesday that it had earned the final starting spot in Sochi that would have gone to Souza. It will now be offered to Santos.
Souza competed in gymnastics at the 2004 and 2008 Olympics, before missing the 2012 Olympics with a hand injury. A vault specialist, she helped Brazil finish eighth and ninth in 2008 and 2004, respectively.