The West Ridge of Moose's Tooth, with the area where the climbers' tracks led to a small avalanche area boxed in red/NPS

A search for two climbers missing in Denali National Park has been scaled back as no sign of the men has turned up and their chances of survival extremely low.

The two were last known to be in the vicinity of the Moose’s Tooth, a 10,300-foot mountain in the park’s Ruth Gorge. Eli Michel, 34, of Columbia City, Indiana, and Nafiun Awal, 32, of Seattle, Washington, were last heard from at 5 a.m. last Friday after they checked in with a friend via an InReach satellite communication device. At that time, the climbers indicated they intended to climb the West Ridge route of the Moose’s Tooth. Concerned when the two climbers did not check in again, the reporting party contacted Denali National Park mountaineering rangers in Talkeetna on Sunday morning.

The West Ridge is "a steep technical route on the Moose’s Tooth characterized by a moderate angle approach to a mix of 60-degree snow, ice, and rock slopes," the park said in a release. "Based on communications with their friend, the team had intended to climb the route in a single, long push. As is typical, to minimize weight and move fast, they did not take overnight gear, nor likely more than a day’s supply of food, water, and fuel."

During the active search mountaineering rangers found indications that the two men were swept off their feet by a small slab avalanche on the evening of Friday, May 5, high on the peak’s West Ridge route. "Several items of the climbers’ equipment, including two ice axes, were observed off the climbing route during aerial searches of the 3,200-foot fall line," the release said. "Multiple ground searches of the heavily crevassed glacier at the bottom of the fall line were conducted via helicopter short-haul in order to reduce exposure to rockfall and avalanche hazards to rescuers. The two climbers were not found."

"Spotters on aerial and ground missions searched both the climbing route and the fall line to the degree that if the climbers were visible on the surface, there is a high probability they would have been discovered," the release added. "Considering the severity of the rocky terrain along the 3,200-foot fall line, the team’s limited supplies, temperatures ranging from 5 Fahrenheit to 20 Fahrenheit overnight, and the duration of time since last contact, search managers have concluded that survival is outside the window of possibility."

Although the search is being scaled back, Denali mountaineering rangers will continue the aerial search for signs of the two missing climbers throughout the next several months, as snow conditions change with the warming temperatures, the release said.