A mother of two young children died Friday after a rock flew off a passing truck and came through the front windshield of her vehicle.

The woman, who has not yet been named, was travelling in the passenger seat of a Subaru Legacy while on vacation with her husband and children when she was struck and killed by an airborne rock, according to East Kootenay Traffic Services.

An RCMP news release issued Saturday said the Calgary family was driving north on Highway 93/95 about 11 a.m. on Friday, October 5, across the Kootenay River bridge in Canal Flats. A large rock, approximately 12 inches by five inches in diameter, came loose from a passing commercial vehicle’s dual wheels and struck the Subaru.

The rock went through the front windshield into the passenger compartment, killing the 37-year-old female passenger.

RCMP said the commercial vehicle was southbound, towing an unloaded lowbed trailer. The suspect vehicle was stopped some time later and seized. The investigation shows that the rock appears to have been lodged between the dual tires on the trailer.

The driver of the commercial vehicle has been been released with no charges at this time, but the investigation is continuing.