The UHP says the crash happened after a rear-end collision pushed the victim's vehicle into oncoming traffic on State Road 36 where a head-on collision took place.
The victims were later identified as 49-year-old Slaone F. Ackman and 29-year-old Trista S. Ackman, from Salt Lake City. Both women were pronounced dead at the scene.
The UHP said that the driver of a third vehicle thought to be involved in the crash left the scene.
On Wednesday morning, the UHP indicated that the driver of the vehicle that left the scene contacted the authorities late Tuesday night.
The UHP did not indicate what role the drive may have played in the crash, which was still under investigation, and that no charges had yet been filed.