Utah teen killed by falling rocks during family vacation at Glacier National Park

She was vacationing with her family at Glacier National Park in Montana.

A Utah teenager died on Monday after being hit by falling rocks while vacationing with her family at Glacier National Park in northwest Montana.

The family was riding in their vehicle at around 7 p.m. when multiple rocks came crashing down from a nearby mountain, landing on the vehicle's roof and shattering the rear window, park officials said.

The 14-year-old girl died before she could make it the hospital.

"A.L.E.R.T. air ambulance responded, but was unable to airlift the girl because of her unstable condition," the park said in a statement Tuesday. "Flight paramedics traveled with her via ground ambulance to Kalispell, MT. The girl died while being transported to a local hospital."

Two other children were also taken to a hospital with minor injures and two adults suffered "significant" bruising.

Officials said the rocks ranged in size, with the smallest being about the size of a fist and the largest about 12 inches in diameter. They said the amount of debris left from the rocks could have “filled the bed of a pickup truck.”

The victim's name is being withheld pending notification of other family members, according to the statement.

"The park extends its deepest condolences to the girl’s family, and thanks its partner emergency care providers for the significant response," the statement said. "The family asks for privacy at this time."

Going-to-the-Sun Road, where the fatal accident occurred, was partially closed for approximately three hours while road crews cleared the scene.

At least one other person had previously died on the road from falling rock, with the most recent incident occurring in 1996, park officials said.

ABC News' Rayquan Taylor contributed to this report.