A huge, unstable chunk of glacier is blocking the route up Mount Everest from Base Camp in Nepal just as peak climbing season gets under way in the Himalayas. 'Icefall doctors' – who fix ropes and ladders on the lower part of the route up the world's highest peak - can find no way around the 100-foot-high (30m) block of ice just under Camp 1. They say the only option is to wait for the ice block, called a serac, to melt – which they hope will happen within days. The delay means preparations are weeks behind schedule for the spring season when weather for Everest ascents is usually best, and fears are growing that climbers will be queuing to reach the summit again this year. Purnima Shrestha, a prominent climber and photographer from Nepal, is currently acclimatising to summit Everest for the sixth time. 'We usually climb between Camp I, Camp 2 and Camp 3 back and forth during this acclimatising process. Delays in the opening of the route have added concerns of possible 'traffic jams' on the peak this year,' she told the BBC from Base Camp. The icefall doctors work for the Sagarmatha Pollution Control Committee (SPCC), which is responsible for securing ropes as far as Camp 2 on Everest. By this stage in April, they would normally have fixed the route as far as Camp 3 but are still blocked by the ice chunk about 600m below Camp 1. 'We haven't found any artificial ways to melt it so far, so we don't have any options other than to wait for it to melt and crumble,' said SPCC base camp coordinator Tshering Tenzing Sherpa. The expected weather window for climbing is until the end of May. Ram Krishna Lamichhane, Nepal's Department of Tourism director general, stated they are considering airlifting rope-fixing teams directly to Camp 2. The situation remains dynamic, as climbers hope for a timely thaw to continue their ascents unobstructed.