A New Hampshire woman apparently drowned in the North Fork of the Shoshone River on Tuesday near Yellowstone National Park.

The body of 56-year-old Susan C. Hartley was found Wednesday afternoon. Park County Coroner Tim Power has made a preliminary ruling that Hartley drowned, according to a statement from the Park County Sheriff's Office, though the official cause of death is pending an autopsy.

Hartley was an employee of Pahaska Teepee Resort, which sits two miles outside the East Entrance of Yellowstone National Park on U.S. Highway 14-16-20. She was last seen at the resort at 3 p.m. Tuesday.

When Hartley didn't report for work at 7 a.m. Wednesday, her coworkers began searching for her.

They found her backpack and walking stick beneath the highway bridge that crosses the Shoshone River just east of Pahaska. Due to the circumstances, they notified the sheriff's office. Search and Rescue was activated at 11 a.m.

Search crews immediately responded to the area with a canine team. But before they arrived, Pahaska employees found Hartley's body in the river directly across from the Pakaska trailhead.

A swift water team was deployed to recover the body, as the river was swollen and moving rapidly from the spring runoff.

The sheriff's office says there were no apparent signs of foul play.