A British reconnaissance in 1951 assessed the route through the Khumbu Icefall to the Western Cwm, hence by-passing Lho La, and in subsequent years this was the line that was followed, so leading to the South Col and the Southeast Ridge. The successful ascent of Everest in 1963 by Americans Tom Hornbein and Willi Unsoeld via the West Ridge and the Hornbein Couloir was achieved by climbing from the Western Cwm to the West Shoulder, well east of the Lho La.