A massive interagency search-and-rescue effort is still underway for 1st Lt. Matthew Kraft who was report missing after he failed to return from a skiing and hiking trip in the Sierra Nevada mountain range.

Kraft was hiking the 195-mile Sierra High Route and his trip was slated to end around March 4 or 5.

Cellphone records pulled by Bridgeport, California, Mono Sheriff department showed that Kraft’s last phone activity was in the vicinity of the Independence area, according to a command release. Kraft’s rental vehicle, a gray Jeep, was also found in Grays Meadows campground above Independence, California.

Multiple local, state and military agencies have been involved in the massive search and rescue that has included aerial and ground operations.

Aerial and ground search teams noted that avalanche activity had been spotted along the Sierra High Route, a command release detailed.

Monday evening, the 1st Marine Division said avalanche experts were being used to clear the east route and assess the avalanche risk in the area.

“Snow instability will remain a challenge as search teams attempt to clear portions of the route,” Inyo Sheriff’s Search and Rescue Coordinator, Sergeant Nate Derr, said in a command release.

“We know the public is very interested in helping with the ground search effort, but due to the extreme hazards in the search area, we are not requesting any outside units at this time," Sequoia and Kings Canyon National Parks Incident Commander Dave Fox said in a command release.

A command release said that Kraft is an experienced hiker who graduated from Infantry Officer Course and Winter Mountain Leaders Course.