The Sherpas killed in the deadliest avalanche to sweep through Everest were the most experienced climbers to work on the mountain, says a B.C. climber.

Realtor Sam Wyatt climbed Everest in 2012 with the help of one of the 12 Sherpas killed Friday from falling ice.

The Sherpas were the advance crew, preparing ropes on the summit's route ahead of the spring climbing season. Four other climbers are still missing and at least four more were injured when the group was struck

"These were amongst the elite of the Sherpas, the teams that were fixing the rope for the mountain," says Wyatt in an interview with the CBC's Gloria Macarenko. "It's just the nature of that route, the south side route has some very serious hazards starting with the Kumbu Icefall."

That region of the mountain is particularly prone to avalanche and debris from avalanches. The avalanche Friday is being called the deadliest day ever on the mountain since climbers began attempting to scale it in 1921.

Wyatt worked with Then Dorjee, one of the 12 killed, a Sherpa who had climbed the mountain a dozen times.

"Incredibly friendly, helpful and kind and an extremely strong mountaineer," says Wyatt. "He was amazing."

Wyatt says Everest's allure remains despite the many deaths that have occurred on the mountain. In May 2011, six climbers, including Canadian Shriya Shah-Klorfine, died within one 48-hour period.

Only Sherpas are climbing the mountains at this time. While climbers from around the world have descended to the region, many bide their time at base camps until the weather breaks starting in early May.

The Sherpas who were killed and injured were preparing ropes along the routes before the official start of the season.

With files from Gloria Macarenko