The downhill race on the Rosa Khutor piste in the mountains above Sochi is the first of six medals to be won on Wednesday.
Hosts Russia will have high hopes of ending the day with another gold in figure skating, courtesy of world and European champions Maxim Trankov and Tatiana Volosozhar.
The Russians have already won the team event in the Iceberg Skating Palace, much to the delight of watching President Vladimir Putin.
Mild weather risks causing problems in the mountains after rising temperatures forced the cancellation of final practice for the women's downhill.
Julia Mancuso, who took bronze behind Hoefl-Riesch in the super combined on Monday, will carry American hopes after a knee injury robbed Vonn of the chance to defend her title.
"Mushy" snow could also play a part in deciding the Nordic combined where German World Cup leader Eric Frenzel takes on 2010 Olympic champion Jason Lamy-Chappuis of France.
In the indoor Adler Arena, American speedskater Shani Davis will be bidding for his third straight gold in the 1,000 metres and aiming to put a dent in the Dutch domination on the ice.
Australian Torah Bright defends her snowboarding halfpipe title against rivals who include America's Kelly Clark, the 2002 winner who is appearing at her fourth Games.
In the luge doubles, Austrian brothers Andreas and Wolfgang Linger seek their third successive Winter Games gold but must defy German world champions Tobias Wendl and Tobias Arlt.
And the puck drops for the start of action in the eagerly anticipated men's ice hockey tournament. Czech Republic play Sweden and Latvia meet Switzerland in the opening group games.
(Writing by Keith Weir, 44 20 7542 8022)
