A survivor told an inquiry yesterday how he watched in horror as mountaineering instructor Chris Walker, 29, and Robert Pritchard, 37, were killed.
Software developer Ritchie Birkett, 29, said he saw the pair desperately plunging their ice picks into the snow as they tried to stop themselves being dragged to their deaths.
He was speaking on the first day of a fatal accident inquiry at Fort William Sheriff Court into the tragedy on Buachaille Etive Mor on 24 February.
It heard that Mr Walker was a freelance instructor employed by Sheffield-based Jagged Globe and had taken two of the company's clients for a winter climb of the notorious Curved Ridge in Glencoe.
Mr Birkett said : "Chris decided not to take the route down through Coire na Tulach. He left us in no uncertain terms that it was not a safe route, because of the avalanche risks. He ultimately made the decision.
"Chris and Robert were up ahead. Suddenly the snow in front seemed to start moving. It became loose and I realised it was an avalanche because it was the whole section of the slope.
"I shouted 'Avalanche'. They turned around and were instantly taken down. The last I saw of them was trying to do an ice axe arrest in to the snow. They instantly went out of sight."
The inquiry continues.