The Khumbu Icefall is one of the most dangerous stages of the route up Mount Everest, a huge mass of giant blocks of ice that move slowly towards the valley. But climbers must cross it if they are to reach the peak. They manage thanks to icefall doctors who install networks of ladders and ropes at the site and adjust them time and again throughout the season as the ice shifts, often at great personal risk. Experienced icefall doctors can see at a glance how safe the ice is “just like a mother can tell what’s wrong with her child when she sees it,” one told dpa. In one of the latest compelling …