Authorities say a slippery mix of rain, sleet and snow may have contributed to a collision that killed three people late Sunday afternoon in southwestern Iowa’s Pottawattamie County. Sheriff’s officials say the accident occurred on State Highway 92 between Council Bluffs and Treynor.

Two people were pronounced dead at the scene, while a third person was taken to a Council Bluffs hospital, where she later died. The victims’ names have not yet been released. A fourth person was hurt in the crash, which occurred about 5:30 p.m. Their injuries were not believed to be life-threatening.

The three who died were traveling west when their car went out of control and collided with a van in the eastbound lane. Officials with the National Weather Service in Valley, Nebraska, said rain was mixing with sleet and snow at the time, and gusty winds may have reduced visibility.