Beijing, China ? On Nov. 9, this message was inscribed in the visitors’ book of a restaurant in the remote southern Chinese village of Litang: “Great food and people. … The mountains around Yading are awesome. Countryside reminds us of home. We’ll be back. – Chris Boskoff and Charlie Fowler, Norwood, Colorado, US.”

Those are the last words that two of America’s most prominent mountain climbers are known to have written.

Since Dec. 18, search teams have been hunting for Boskoff and Fowler. On Christmas morning, a renewed team was planning to set out into the mountains in search of the two.

This has been a difficult month for the American mountain climbing community. Last Wednesday, an Oregon sheriff called off the search for two missing climbers who had been trying to scale Mount Hood. A third climber in that group had previously been found dead in a snow cave near the summit.

Boskoff and Fowler are well known among avid climbers. Climbing magazine has described Fowler, 52, as “long revered as one of the world’s leading climbers.” Boskoff, 39, who runs a Seattle-based expedition company, Mountain Madness, has climbed “more high-altitude summits than any other woman in the world,” the magazine said. Those included Mount Everest, Mont Blanc, Ama Dablam and Lhotse.