MISSOULA, Mont. (AP) — A semi-tractor trailer went off Interstate 90 in western Montana, killing a 6-year-old Florida girl and injuring a 1-year-old girl, the Montana Highway Patrol said.

A 34-year-old woman from Hudson, Florida was driving the truck with a the girls and a 10-year-old boy in the sleeper cab when it drifted off the side of the road just before 1 a.m. Sunday near St. Regis, Sgt. Sean Finley said Monday.

The driver tried re-entering the road, causing the trailer to overturn into the median, forcing the cab into the median, as well. The truck hit several trees before coming to rest.

The driver and the 10-year-old boy were not injured. The victim’s name has not been released.