Rochester, MN (KROC AM News) -  Dense fog developed across southeast Minnesota early Tuesday, creating hazardous driving conditions as visibility was at or near zero in many areas.

The dense fog may have played a role in a serious traffic wreck in Dodge County around 5:30 a.m.

The head-on crash occurred on Highway 56 about 2 miles north of Hayfield and at last check, that section of the road was closed.Two people were hurt in the wreck and one was unresponsive and CPR was performed on the person.

Besides the thick fog, temperatures have slipped below freezing in some areas, which could produce slick roads.