SLIPPERY ROCK, Pa. -- A Harrisville woman and her 5-year-old granddaughter were injured when their 2001 Ford Escape veered off of William Flynn Highway and struck several trees.

The accident occurred at about 3:45 p.m. Saturday in Slippery Rock Township, Butler County.

Firefighters needed to extricate both occupants of the vehicle after it rolled onto its side.

The woman was flown to UPMC Presbyterian with serious injuries and the child was taken to Children's Hospital.

The cause of the accident is unknown at this time. Pennsylvania state police in Butler are investigating.

Assisting at the scene were Slippery Rock VFD, Unionville VFD and Butler Ambulance Service.