A Calgary climber says the deaths this week of 13 Sherpas on Mount Everest are sad but an unfortunate risk for those who routinely make the trek.

At least 13 Nepalese guides were killed in an avalanche on Friday as they were trying to fix ropes for climbers and three more are still missing. Calgary climber Andrew Brash says accidents like this make him think about the impact increased climbing activity has on locals.

"I feel badly because there are Sherpas up there making a living doing this," said Brash, who summitted the mountain in 2008. "They're not doing this for personal self-realization and all those kinds of things. They're doing it for employment and you have to feel some guilt about that if you're involved in this Everest climbing activity."

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The avalanche Friday happened at about 5,800 metres in an area known as the "popcorn field" because of its bulging ice. (CBC)

Brash says the avalanche happened in the most dangerous part of the climb and it was only a matter of time before a group would get caught in the wrong place.

In the early days of climbing the mountain, Brash says Western climbers worked with Sherpas to fix the route.

But he says that has changed over time and now most of the work is done entirely by locals.

'You have a bond with them': climber

Alan Hobson also climbed Mount Everest and says it's particularly sad given that guides — the people who take on risk to help other climbers — died.

He says he hasn't forgotten their own contribution to his summit in 1997.

"You have a bond with them that will last a lifetime even if you don't see them again," Hobson said. "You feel for them, you know the community. This will have a massive impact."

The avalanche happened near where three guides died in 1982 when Laurie Skreslet summitted.

He says it's sad to see it happen again — but not surprising given the number of people on the mountain now.

"When people are concerned about the state of safety on Everest, I'm not sure there is a state of safety on Everest," he said. "The mountain is risky. People underestimate the damage that can happen on a mountain like that because so many people are getting up it."

Hobson says he is talking to other climbers about contributing to a trust fund for those who died Friday.

The disaster is the deadliest ever to happen on Mount Everest.