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Multiple agencies searched for a sixth day on Saturday for a marine who went missing on a skiing trip in California's Sierra Nevada mountains.

Mono County Sheriff’s Office said Marine Corps Lieutenant Matthew Kraft was reported missing after not showing up on his scheduled return date.

Officials say Kraft’s itinerary went through the Sierra High Route, a cross-country hiking route through the Sierra Nevada that is nearly 200 miles long.

He is believed to have started out of Kearsarge Pass on Feb. 24 and was supposed to hike out near the Twin Lakes area by Bridgeport on March 4 or 5.

On March 4, Kraft’s father contacted police after not hearing from his son.

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Lt. Matthew Kraft was reported missing to local law enforcement while on a back-country skiing trip on the Sierra High Route. Monroe County Sheriff's Dept

Mono County deputies started searching for Kraft in the Bridgeport area Monday and Inyo County Sheriff’s Office searchers joined the effort the next day. Pings from Kraft's last cell phone activity showed that he was in the Independence area in Inyo County.

Multiple agencies are now assisting the search for the marine, including the Marine Corps, California Highway Patrol and Yosemite National Park.

A spokeswoman for Inyo County Sheriff's Office, Carma Roper, said search teams were scouring an area of roughly 400 square miles along the Sierra High Route.

"Weather conditions are a challenge," Roper said Sunday. "In addition to winter storms that bring heavy snow and high winds, there are significant avalanche risks in the back country. Yesterday aerial search crews noted several avalanches throughout the Sierra back country and along the Sierra High Route."

On Saturday, rescuers deployed a snowcat to rope-tow search and rescue team members on skis up to the Onion Valley parking area above Independence, where rescuers will clear as much area as possible.

Officials say search and rescue crews will work as long as weather allows, but another storm was anticipated through the weekend.

Kraft's marine division shared a post on Facebook Saturday to update followers on the search for Kraft.

"To the overwhelming majority who have expressed concern for the well-being of 1stLt Kraft: thank you for your well wishes," it said.

Yuliya Talmazan reported from London, and Matthew Devine from New York.