Foggy conditions plagued the first run of the event, during which 17 of the 83 skiers failed to finish, and eventually forced postponement of the second run until Thursday.
Not only did Vonn lose a chance at a third medal of the Olympics, her crash also affected teammate Julie Mancuso.
Mancuso followed Vonn down the course and her first intermediate time was the best of the morning. But because Vonn was still sprawled against a fence on the lower part of the course, officials raised a flag indicating Mancuso should stop her run for safety reasons.
Mancuso was given a second chance later in the run, but her time was 1.30 seconds behind leader Elisabeth Goergl of Austria, leaving the American in 18th place heading into the afternoon's second run.
Taina Barioz of France was in second place, followed by Austrian skiers Kathrin Zettel and Eva-Maria Brem.
Officials delayed the start of the second run, but the fog remained thick and the remainder of the event was eventually pushed back a day. Goergl, who won the bronze medal in the downhill behind Vonn and Mancuso, will be trying for her first gold of the Olympics.
Vonn was 0.35 of a second faster than Goergl through the third timing check point and was less than 20 seconds from the finish line when she skidded out of control.
She then hit a bump and slid into the catch fence.
"I got a little bit too inside and lost my outside ski," Vonn said. "My knee came up and hit my chin. I got all tangled up and hit the fence. I hurt my (pinkie) finger and need to get it examined."
That examination showed the finger was broken, which leaves her appearance in the slalom event on Friday in doubt. The slalom is Vonn's weakest discipline.
Vonn won the downhill gold medal early in the Olympics, the first American woman to do so, and also took the bronze medal in the super-giant slalom. She failed to finish the super combined event after turning in the best time in the downhill portion of the competition.