Lindsey Vonn's Winter Olympic dream ended in screams of pain on Sunday after she crashed out of the women's downhill won by her American teammate Breezy Johnson.

The American star had been trying to claim the fourth Olympic medal of her career despite suffering a ruptured anterior cruciate ligament in her left knee just over a week ago, but her race ended after just 13 seconds in Cortina d'Ampezzo.

She cried in anguish and pain after her violent crash high up the course, medical staff quickly surrounding the distraught 41-year-old on the Olimpia delle Tofane piste where has enjoyed much success in the past.

The 2010 Olympic downhill champion hit the firm snow face first soon after pushing off from the gate.

She then rolled down the slope with her skis still attached, which could likely cause further serious damage to her knee.

Vonn's Olympic dream now lies in tatters after her audacious bid to achieve the seemingly impossible, an attempt which ended with her being taken away in a helicopter as fans in the stands saluted her with loud applause.

Johan Eliasch, the president of the International Ski Federation (FIS) who was watching the race in Cortina, said Vonn's crash was "tragic, but it's ski racing I'm afraid".

"And I can only say thank you for what she has done for our sport because this race has been the talk of the Games and it's put our sport in the best possible light."

Eliasch added: "I hope she will have a speedy recovery and back on skis very, very soon.

"A lot of people are going to say she shouldn't have been racing today (with) that type of injury. It's obviously her decision."

Johnson, who was already in the leader's chair after her aggressive run down the slope, held her face in shock after Vonn's crash, which completely changed the complexion of the race.

Already the reigning world downhill champion, Johnson finished in front of Germany's Emma Aicher by just 0.04s with Italy's speed specialist Sofia Goggia taking bronze in front of home fans.

Vonn said ahead of the Games that she was planning on also competing in the team combined event on Tuesday and the super-G two days later.

But that now looks unlikely, a potential long lay-off perhaps heralding the end of her comeback to skiing in her early 40s. (AFP)