A fellow climber who summitted Mount Everest with Irishman Seamus Lawless has said he suspected he may have been off-rope when strong winds knocked him off a section of blue ice.
Speaking on RTÉ's Morning Ireland, Noel Hanna said it was a "freak accident".
Mr Lawless, who worked as a professor at Trinity College Dublin, fell during his descent from the mountain two weeks ago, at an altitude of 8,300 metres.
A fundraising appeal was launched to help locate the 39-year-old, but last week the search was called off.
Mr Hanna, who led the expedition with Mr Lawless, said that there were perfect conditions and no queues on the mountain as he and Mr Lawless reached the top of the mountain with two others.
He said everyone was in good form, the team spent 15 to 20 minutes on the summit taking photographs and then descended to the area known as the balcony.
At this point they shared oxygen while Mr Lawless, the strongest of the team, continued his descent with a Sherpa before he fell.
Mr Hanna said that Seamus had put in two to three years of training and may have been caught by a freak wind.
He said they searched until dark to find Mr Lawless but the winds had picked up and it was becoming dangerous to continue.
Kevin Hynes, from Ballinasloe, Co Galway, died after he turned back during the climb before reaching the summit.