Two people have died after a plane crashed in Denali National Park and Preserve in Alaska earlier this week.

Officials have determined that the plane’s pilot, Jason Tucker, 45, and passenger Nicolas Blace, age 44, are likely to have died in the crash.

The Alaska Air National Guard Rescue Coordination Center was first alerted on Wednesday about an aircraft that had failed to arrive in Denali National Park’s southwest preserve. On Thursday, the Air National Guard located the PA-18 aircraft’s wreckage in a ravine in the park near the Yentna River.

“The search crew was unable to land at the accident site due to the steep terrain, but they observed that survivability of the crash was unlikely,” according to a Denali National Park press release shared with USA TODAY.

More:‘Burnt down to ashes’: Families search for missing people in Maui as death count climbs

Later Thursday, two Denali National Park mountaineering rangers went to the site of the crash to assess the likelihood of reaching the plane using a helicopter short-haul line. The rangers determined that the short-haul mission was not feasible.

“Hazards under consideration include the 460-foot length of the short-haul line, inadequate helicopter rotor clearance due to the narrow width of the ravine, loose rock lining both walls of the ravine, and the lack of shoreline for miles above and below the rapidly flowing creek at the base of the ravine,” it states.

Additionally, Alaska State Troopers were also alerted on Thursday about a hunter who was stranded at an airstrip outside the southern border of the preserve after his pilot had failed to return and pick him up.

“Upon retrieving the stranded hunter, Alaska State Troopers learned that his pilot (Tucker) and his hunting partner (Blace) departed the initial airstrip on Wednesday intending to fly to a Dillinger River airstrip near the western boundary of the preserve,” the release states. “Tucker intended to drop off Blace, then return for the other hunter, which never happened.”