The woman who fell 15m down an "evil" crevasse in the side of Mt Ruapehu was lucky she didn't have to climb down the mountain in the dark with her rescuers, the local rescue chopper pilot says.
A mountaineering group called police around 2.40pm on Saturday to say a woman in their group had fallen down the crevasse in the Whangaehu Glacier on the eastern side of the mountain.
They could talk to her but not see her - and pictures taken at the crevasse show why. It's a dark pipe little more than a metre wide at the top, with no end in sight.
The crevasse was "evil" looking, said Greenlea Rescue Helicopter pilot Nat Every, who came to their aid in blustery conditions.
Seeing their mate "go rattling down a drain pipe in the mountain" would have been terrifying, Every said. Police said the woman was lucky to escape serious injury.
The helicopter was immediately sent to the glacier from Taupo, via the Chateau Tongariro Hotel where it picked up members of the LandSAR Ruapehu Alpine Rescue Organisation (Raro).
Flying conditions were extremely challenging last night, with strong westerly winds barrelling down a gully on the side of the mountain, according to Greenlea Rescue Helicopter pilot Nat Every.
"It's like if you imagine going up in a canoe and trying to do a job just below Huka Falls."
The team stripped the chopper down, turfing out everything from a stretcher to drink bottles to lower its weight before making the difficult flight to rescue the woman.
"There's a river that flows out of the crater lake that creates a sort of ... gully ... which is like a drainpipe on the mountain," he said. "Any wind from the west funnels down the eastern side, and it's pretty turbulent and rough with a lot of downdrafts."
That made it a technical challenge to get up and too difficult to stay. Every took the four rescue team members up the mountain in pairs, dropping them at a convenient small platform around 100m from where the woman had fallen.
The group were around 7-8000 feet up the mountain - a similar height to the peak of nearby Mt Ngauruhoe.
Every based the chopper at the Tukino ski field base area on the eastern slopes of Mt Ruapehu and returned to the scene as required.
The rescue team used ropes and harnesses to extract the trapped woman from the crevasse around 6.40pm. She was reportedly in good health and good spirits.
Her five companions were also brought back to the hospitality of the Tukino Lodges.
Every was full of praise for the rescuers, who were fully prepared to bring the woman home by foot if necessary.
"By the time we picked them up it was dark, windy, the cloud was dropping," he said. "If conditions had deteriorated any further they would have been walking back a really long way."
"It's very important in what I do that you don't think you're pressurised in any way - they're entirely self sufficient on their own. My job is to get these people in to do their job."