Deadly Everest climbing season prompts questions about safety

It's been one of the deadliest climbing seasons on Mount Everest in recent history, prompting some to question whether the volume of climbers is sustainable. This year, at least 12 people have died on the mountain -- 9 foreign nationals, and 3 Nepalis, including Australian climber Jason Kennison – while five are missing -- 1 foreign and 4 Nepalis.

Queues to scale Mt Everest are long - and growing. (AAP) Source: AAP