USA skier Bode Miller has said that the Rosa Khutor downhill piste "can kill you".
Slovenian downhill skier Rok Perko crashed in practice, while Miller's USA teammate Marco Sullivan narrowly avoided serious injury before the 36-year-old took to the slope.
"If you are not totally focused and paying attention, this course can kill you," Miller told BBC Sport.
"It's very treacherous. This course has teeth everywhere.
"The top is aggressive, speeds are so high and the turns are so swingy and bumpy that you can hook an edge anywhere."
Miller's compatriot Shaun White withdrew from the snowboard slopestyle competition, while Maria Hoefl-Riesch of Germany has also criticised the piste.