The start of Tuesday's race was delayed by 3½ hours because of fog hanging over the course and the skiers began in waning light at 2:30 p.m. Even before Vonn's crash, a course worker fell and also had to be airlifted. He was reported to have broken his nose.
All the delays made for flat light when Vonn raced.
"Lindsey did a great job on top and Lindsey has won a lot of races in flat light so the flat light was definitely not a problem," U.S. Alpine director Patrick Riml told the AP.
"We are upset obviously with what happened, but if you don't know the facts and why they decided to start and what the weather forecast was it's hard to say without any reasoning," Riml said. "And they probably had a reason, otherwise they wouldn't have started."
It was difficult to pinpoint when Vonn lost control as she came off a left turn into the jump.
"She jumped a little bit in the wrong direction and started to correct that a little bit in the air and put a lot of pressure on the outside ski exactly in the landing and she couldn't hold the pressure and then (she crashed)," International Ski Federation women's race director Atle Skaardal said.
Skaardal defended the decision to race.
"I can confirm that the visibility was great, there were no problems, and the course was also in good shape," he said. "I don't see that any outside factors played a role in this accident. ... The other factors were like they were supposed to be for ski racing."
Two years ago, Vonn pulled out midway through the last worlds in Garmisch-Partenkirchen, Germany, because of a mild concussion. At the 2010 Vancouver Olympics, Vonn skied despite a severely bruised shin to win the downhill and take bronze in the super-G.