In this May 18, 2013 file photo released by mountain guide Adrian Ballinger of Alpenglow Expeditions, climbers make their way to the summit of Mount Everest, in the Khumbu region of the Nepal Himalayas. (AP Photo/Alpenglow Expeditions, Adrian Ballinger, File)
In this May 18, 2013 file photo released by mountain guide Adrian Ballinger of Alpenglow Expeditions, climbers make their way to the summit of Mount Everest, in the Khumbu region of the Nepal Himalayas. (AP Photo/Alpenglow Expeditions, Adrian Ballinger, File)