Garrett Madison, a 44-year-old US mountaineer, conquered the rare Mount Everest region "triple crown" in a single season, a hiking firm said on Friday. He climbed 8,516-metre-high Lhotse peak, the world's fourth tallest peak, on Thursday, a day after he made his 13th ascent of Everest at 8,849 metres. Notably, Seattle-based Madison climbed the 7,855-metre-high Nuptse peak on May 8.