Ed Wardle, a TV director, camera operator and adventurer who was expected to make an ascent of the world's highest peak as part of an NBC TV documentary crew, admitted the tragedy led him to question the venture.
The avalanche struck at around 6.45am local time in an area known as the "popcorn field", just above the mountain's base camp at 19,000ft.
Sherpa guides had climbed up the slope early in the morning to fix ropes for climbers and prepare the route for mountaineers when the avalanche hit.
Mr Wardle, 43, an experienced Everest climber who has produced a documentary on the mountain, said five of those who died were Sherpas - members of the ethnic group in eastern Nepal - working for the team he was with.
He said: "The atmosphere here at base camp is one of shock and now of grieving.I believe it's the worst disaster in Everest history if not all mountaineering. For something like this to happen makes the whole thing seem pointless to me. And I believe that will be the same for many people here.
"One of the most horrific sights I ever saw on Everest was seeing the bodies being airlifted on longlines below the helicopters. They've been brought back down to base camps and will eventually be brought down to their families.
"The mountain is closed for now. Nobody will be climbing.
"People come here to take a risk. We understand those risks. But when something like this happens, we all have to question what we're doing here."
The accident comes during the peak climbing months of April and May as hundreds of climbers converged at base camp in the hope of scaling the summit.
Mr Wardle added: "I think that many of the expeditions here will pack up and go home.
"For this number of people to die at the very beginning of the season is completely unacceptable."