The two mountaineers who died on Mt Taranaki had little chance of surviving for two nights and a day in their shallow hole in the hard snow and freezing wind, says a leading local guide.
New Plymouth-based Ross Eden, who is also the editor of the New Zealand Alpine Club's guidebook for the mountain, told the Herald: "I wouldn't expect to survive if I was going to dig in and not get completely out of the wind."
Mr Eden was commenting on a report from the search and rescue team that Hiroki Ogawa and Nicole Sutton's "snow cave" was in fact only waist deep, leaving them exposed to the full force of the wind.
The MetService forecast for Saturday indicated cloudy periods would give way to drizzle at night, with a northwesterly rising to gales about the peak. The wind-chill was forecast to be -14C at 9pm.
Reports have suggested the climbers scraped out their shallow hole just below the crater area at about 2400m on the 2518m mountain - and that they were part of a larger group that arrived at the top of the East Ridge at about 7pm.
The sun set at 7.54pm on Saturday.
Mr Eden said the snow around the crater area was mostly hard at this time of year and it appeared the climbers might not have been carrying snow-shovels.
"It shows that if it was only waist deep, it was difficult to dig. It would have been only ice-axes I imagine."
"I wouldn't think that they had sleeping bags. They wouldn't have planned to spend the night out given the [poor] weather forecast."
He said that arriving at the top of the East Ridge climb in the crater area at 7pm was "just ridiculous". It suggested something had gone wrong on the climb to slow them down - gear failure, or perhaps an injury.
The Taranaki East Ridge climb in spring is graded at 2 on the Aoraki-Mt Cook system; the most commonly-used climb on Aoraki-Mt Cook, the Linda Glacier route, is graded 3.
Mr Eden said the East Ridge ascent typically took up to 4 hours to complete in winter and spring without using a rope. Using a rope, and snow-stakes or ice-screws, more than doubled that time.
He said a rope wasn't usually used on the climb by fit and competent climbers.