A massive block of glacier is blocking the route to Mount Everest just as peak climbing season is getting underway, raising fears of dangerous queues on the world's highest peak.

The ice block, known as a serac, stands 30m tall and sits nearly 600m below Camp 1 on the Nepalese side of the mountain, according to the BBC.

Icefall doctors, the specialist Sherpas responsible for fixing ropes and ladders on the lower section of the route, spent days searching for a way around it and found none.

"We haven't found artificial ways to melt it so far, so we don't have any options other than to wait for it melting and crumbling itself," Tshering Tenzing Sherpa, the base camp coordinator for the Sagarmatha Pollution Control Committee, told the BBC.

By this time in April, the route would normally be fixed as far as Camp 3. The icefall doctors arrived three weeks ago but remained blocked well below Camp 1. Sherpas say the serac's lower section is already weakening and they hope it will collapse within days, but the delay is compressing the climbing window significantly. Favourable weather on Everest is typically only reliable until the end of May.

"This is not something you can fix or move," Himal Gautam, a spokesperson for Nepal's Department of Tourism, told reporters. "It's natural. We can only wait and assess."

The tourism department said it was exploring the option of airlifting rope-fixing teams and equipment directly to Camp 2 to open the upper route while waiting for the obstruction below to clear. "We will wait for the ice to melt at the place where there is an obstruction and work there when everything is safe," Ram Krishna Lamichhane, the department's director general, was quoted as saying by the BBC.

Prominent Nepali climber and photographer Purnima Shrestha, currently acclimatising at the base camp ahead of what would be her 6th Everest summit, said the delay had added to concerns about overcrowding.

"We usually climb between Camp 1, Camp 2 and Camp 3 back and forth during this acclimatising process,” she told the British broadcaster.

“Delays in the opening of the route have added concerns of possible traffic jams to the peak this year.”

Even if the route was opened soon, she said, the climbing window could be narrow, with large numbers of climbers compressed into a shorter period.

Nepal issued 367 climbing permits for Everest this spring, most of them to Chinese nationals. Fees for foreigners have been increased to $15,000 this year from $11,000 and doubled to $1,000 for Nepalis.

Nepal has been tightening its permit system and raising prices since images of climbers queuing on the mountain went viral in 2019. Despite the Iran war's impact on fuel costs and international travel, expedition operators said demand had held up, with mountaineering affected less than trekking.