That left her 0.30 seconds back of Liechtenstein's Tina Weirather. Italians Elena Fanchini (1:51.43) and Sofia Goggia (1:51.44) had the second and third fastest times, respectively.
World Cup overall leader Mikaela Shiffrin of the United States completed her run in 1:52.74 to finish with the 20th fastest time.
Vonn, who has 18 career World Cup race wins in Lake Louise, could make up some ground on Stenmark as the Canadian resort west of Calgary will host the start of the speed season with downhill races on Friday and Saturday and a Super-G on Sunday.
In her career, Vonn has won 14 downhill races in Lake Louise and four Super-Gs.
Training runs will be held again on Wednesday and Thursday.
(Reporting by Frank Pingue in Toronto; Editing by Toby Davis)
