MIFFLIN COUNTY, Pa. (WHTM) — Black ice in Mifflin County caused a minor school bus accident on Tuesday morning, the Mifflin County School District Superintendent Vance Varner said.

The bus encountered black ice on Parchwood Drive around 9 a.m. on Dec. 6, which caused it to travel off the road, stopping against a tree that prevented the bus from completely tipping over, Varner said.

Three elementary school students and the driver were on board the bus, Varner said, but none of them were injured. They were evaluated on scene and were not taken to the hospital, Varner told abc27.

Varner said the district’s high school nurse was driving behind the bus on her way to school when the accident happened, so she was able to immediately call 911 and help the students.

The students were evacuated through the emergency door and were picked up to go to Strodes Mills Elementary School, Varner said.