Natalie DiBlasio

USA TODAY

An avalanche left 12 dead and four missing in the worst-ever recorded disaster on Mount Everest.

With peak season just days away, Sherpas and guides are busy preparing for the trek up the highest peak in the world.

"The Sherpa guides were carrying up equipment and other necessities for climbers when the disaster happened," a spokesman for Nepal's Tourism Ministry, Mohan Krishna Sapkota, told the AFP news agency.

Before a climber begins the assent, hired Sherpas set up camps at higher altitudes and fix routes and ropes on the slopes above.

The Sherpa guides had gone early in the morning to fix ropes when the avalanche hit them just below Camp 2 at about 6:30 a.m., Nepal Tourism Ministry official Krishna Lamsal said from the base camp where he is monitoring rescue efforts.

Survivor Dawa Tashi — one of two Sherpas who were injured and airlifted to Nepal's capital, Katmandu — was in the intensive care unit at Grande Hospital with several broken ribs.

Tashi told his visiting relatives the Sherpa guides were delayed because of the unsteady path. Suddenly, the avalanche fell on the group and buried many of them, Tashi's sister-in-law Dawa Yanju told the Associated Press.

Hundreds have died attempting to reach the peak, many of them Sherpas. The Sherpa people are one of the main ethnic groups in Nepal's alpine region, and many make their livings as climbing guides on Everest and other Himalayan peaks.

Before this avalanche, the worst recorded disaster on Everest had been a snowstorm on May 11, 1996, that killed eight climbers. Six Nepalese guides were killed in an avalanche in 1970.

More than 4,000 climbers have scaled the summit since 1953, when it was first conquered by New Zealander Edmund Hillary and Sherpa Tenzing Norgay.

Adrian Ballinger, founder and head guide of Alpenglow Expeditions, has climbed the Everest six times and is leaving for his seventh trek on Saturday.

"Everest is an incredibly dangerous place," Ballinger says. "It's a natural beast. This is an accident all of us know is a constant possibility."

Ang Tshering of the Nepal Mountaineering Association said the area where the avalanche hit is nicknamed the "popcorn field" for its bulging chucks of ice.

As soon as the avalanche hit, rescuers and fellow climbers rushed to help.

Contributing: Associated Press