WEST GLACIER, Mont. (AP) — A 26-year-old Pennsylvania woman drowned after being swept over a waterfall on the east side of Glacier National Park, park officials said.

The woman fell into the water above St. Mary Falls at around 5:20 p.m. Sunday. She was washed over the 35-foot (11-meter) tall waterfall and trapped under water for several minutes, the park said in a statement.

Bystanders pulled the woman from the water and administered CPR until emergency responders arrived. She was declared dead at 7 p.m., park officials said.

The woman’s death is under investigation and an autopsy is planned.

Her name was being withheld until family members could be notified.

Drowning is one of the leading causes of death in Glacier National Park, according to the National Park Service.