DENALI NATIONAL PARK AND PRESERVE, Alaska (AP) — Aerial and limited ground searches were underway Monday in Alaska for two overdue mountain climbers whose last known tracks disappeared at the site of an avalanche, officials said.

Eli Michel, 34, of Columbia City, Indiana, and Nafiun Awal, 32, of Seattle, were last known to be near Moose’s Tooth, a 10,300-foot (3,140-meter) mountain in Ruth Gorge, about 12 miles (19 kilometers) southeast of Denali, North America’s tallest mountain, officials said in a statement.

The two last checked with friends via a satellite communication device on Friday morning, when they said they were planning to climb the West Ridge route along Moose’s Tooth.

Their friends contacted park mountaineering rangers in nearby Talkeetna on Sunday when they hadn’t heard again from the climbers.

Rangers on Sunday found the climbers’ unattended tent and ski tracks heading to the base of the route. There, they found the climbers’ skis, left behind when they apparently switched to crampons for the climb.

Rangers then followed boot tracks continuing up the West Ridge into a recent small slab avalanche. “The tracks do disappear at the avalanche,” park spokesperson Maureen Gualtieri said in an email.

No other tracks were found Sunday.

The aerial search Monday was focusing on the avalanche’s runout zone, or the lower portion of the slide path. The area also is marked by many crevasses.

The ground search would be limited due to crevasses and overhead dangers such as falling rock, ice and any additional avalanches, Gualtieri said.