The women were among 13 people aboard a motorboat that clipped a houseboat and overturned Thursday morning.
The Kane County Sheriff's Office said in a written statement one woman was killed in the crash. Two other women were unaccounted for. They were identified as Jessica Jackman, 22, of South Jordan and Valerie Rae Bradshaw, 29, of Sandy.
Jackman's father, Adrian Jackman, was at the wheel of the boat and may have been distracted by some of the six children aboard. Jackman apparently veered at the last minute but was unable to avoid the collision.
The boat overturned in water estimated to be 400 feet deep. Divers from the sheriff's department and National Parks Service were using sonar and remote-controlled cameras to look for the missing women, the Salt Lake Tribune said.