USA-1 teammates Elana Meyers and Lauryn Williams hold a comfortable lead over Canada-1 and USA-2 after two runs of women's Olympic bobsled.
Williams is seeking to become just the second athlete to win a gold medal in the Summer and Winter Olympics. She and Meyers completed two heats at the Sanki Sliding Center track in 1 minute, 54.89 seconds on a rainy Tuesday night.
The Americans lead Canada's Kaillie Humphries and Heather Moyse by 0.23 seconds heading into Wednesday's two runs.
Americans Jamie Greubel and Aja Evans are third, 0.56 seconds back.
Celebrated hurdler turned bobsledder Lolo Jones and teammate Jazmine Fenlator in USA-3 are 11th.
Jones took up bobsled to keep chasing her dream of winning a medal after failing in the 2008 and 2012 Summer Games.