A large ice chunk is blocking the climbing route to Everest’s summit, risking delays in the summit season at the world’s highest peak, according to officials. A team of highly skilled mountaineers, known in Nepal as “icefall doctors”, began fixing ropes and ladders on Mount Everest last month to prepare for the coming spring climbing season. But a dangerous serac – a block of glacial ice – above the already treacherous Khumbu icefall has disrupted their work for nearly two weeks. “We are waiting...