At least one person is dead and two others have been injured in a small plane crash in a remote area of Olympic National Park in Washington, authorities said.

The incident occurred on Tuesday evening at approximately 6:50 p.m. when park rangers were notified of a crash in the Quinault area of Olympic National Park on a steep slope north of the Irely Lake Trailhead, according to a statement from the National Park Service.

“Rangers immediately coordinated a response with Naval Air Station Whidbey Island Search and Rescue,” officials said. “The three occupants of the plane — a Murphy SR3500 Moose — were transported to a Level 1 Trauma Center.”

Authorities said that two occupants were being treated for their injuries and that one person died due to the crash.

Officials have not yet publicly identified the people involved in the incident and have given no details about what might have caused it in the first place.

The cause of the accident is unknown and is currently under investigation by the National Transportation Safety Board.