Mt Omi Tso Go stands 6332m above sea level in Nepal’s Rolwaling Valley and until this year no-one had attempted to climb it.
Mr Henehan is the only New Zealander in the four-person team which will attempt to climb the remote giant this month.
The team’s attempt to be the first to climb the peak, planned over the past three years with mountaineers the second-year geography teacher at Waitaki Boys’ High School met while working as a mountain guide in Norway, was almost halted by an American climber, John Kelley. He took on the mountain alone in February and came tantalisingly close, turning back just 150m from the peak, lashed by winds that made it difficult to stand.
"It’s really cool that it’s an unclimbed peak," Mr Henehan said before he left for the attempt last week.
"Technically, it’s not going to be anywhere near what we’ve done in the past, but — all coming together — it is still going to be slightly technical and with the altitude and the conditions it’s going to be a massive, huge challenge," he said.
The Nepalese man on the crew, Jyamchang Bhote, was a certified International Mountain Guide, who Mr Henehan said had climbed Mt Everest eight times.
Lisa Kvalshaugen Bjarum, of Norway, and Mans Gullgren, of Sweden, the other team members, were also both experienced mountaineers.
Mr Gullgren, who is a photographer, would be documenting the trip.
Because the American climber had ventured up the mountain alone, "hopefully as a team, we can push it a bit further", Mr Henehan said.
However, as the conditions were a major factor, he was only "banking on maybe a 20% chance of actually getting up".
"I don’t want to hurt myself.
"I don’t want to not come back," he said.
