Kathmandu, April 27 -- "It's clear. It's not possible."

That blunt assessment from a joint inspection team has effectively stalled this year's Everest climbing season, as a massive serac perched above in the Khumbu Icefall continues to threaten the only viable route to the summit of Mount Everest.

After multiple field inspections, including aerial surveys and drone-based mapping, experts say there is currently no safe alternative path around the unstable wall of ice. This has left hundreds of climbers stranded at base camp, waiting for a natural resolution that no one can predict.

One theoretical option-linking 15 to 20 aluminium ladders to scale the serac-has already been dismissed as too dangerous. Each ladder, typically about four m...