A series of poor decisions and missed opportunities may have contributed to the deaths of two climbers after they spent two freezing nights stuck near the summit of Mt Taranaki.
Auckland couple Nicole Sutton, 29, and Hiroki Ogawa, 31, were part of a New Zealand Alpine Club annual Labour weekend trip last year.
In New Plymouth this week, an inquest into their deaths heard emotional evidence and highlighted potential gaps in the rescue mission.
Coroner Chris Devonport will now sift through the series of communication errors and decisions on the use of resources - as well as the couple's own decisions - to decide if they had any bearing on the deaths.
One of the key factors will be a decision not to fly a large group of skilled volunteers from Ruapehu Alpine Rescue Organisation (Raro) to New Plymouth, forcing them to drive the four-hour journey, and potentially delaying rescue efforts by up to 12 hours.
The lawyer for the Ogawa and Sutton families, Hanne Janes, described it as "one of the abiding sorrows" that the families were not told of the delay in the Raro team's arrival.
The families would have chartered a commercial helicopter or used one of their contacts in the area to transport the volunteers, she said.
But on the last day of the inquest, it was revealed a non-rescue chopper pilot in Taupo had told National Park police he was available, but a "communication mix-up" meant the incident management team in New Plymouth believed poor weather had ruled out all flight options.
However, police insisted that poor weather in the National Park area meant even if the Taupo pilot had made it across, he might not have been able to land or take off.
They also ruled out using a Royal New Zealand Air Force Iroquois to transport the teams, or sourcing a helicopter from another region.
The RNZAF and police agreed the Iroquois should remain in New Plymouth for the rescue, as sending it elsewhere risked it not being able to return if weather closed in, and being without a chopper if the Taranaki Rescue helicopter was called out to another emergency. "The best use in my opinion was to leave it where it was, ready to go," said Senior Sergeant Thomas McIntyre, operations manager of the Labour weekend rescue.
Also under scrutiny was the use of an e-text system to contact the Raro members, which was issued at 3am on Sunday. Only three replied and were ready to go at 6am.
It was 9am before a further 13 who responded to the call for help were ready to go, and by that stage the weather was too poor to fly.
Sergeant Bill Nicholson, the central district search and rescue co-ordinator, defended the method, saying it was a "marvellous system" that "works really well" in other areas.
Police acknowledged that communication had been flagged as an issue in a post-rescue debrief, where 10 "learnings" were identified.
Dr Ogawa and Ms Sutton had stayed behind to summit the mountain with fellow trampers John Salisbury and Kirsten Spencer after the rest of their group had "bailed" due to bad weather and cold.
But as the foursome headed down the north ridge, it is believed Ms Sutton slipped and knocked into Ms Spencer, who fell and injured her leg.
Ms Spencer and Mr Salisbury descended together, also spending a freezing night on the mountain at 1500m, while Ms Sutton and Dr Ogawa got down only 200m before digging in for the night at 2318m.
They spent 36 hours in freezing conditions before they were found about 7.30am on Monday, October 28, by a team of rescuers who heard Ms Sutton calling out for help.
Dr Ogawa was already dead. Ms Sutton passed away in the arms of rescuers about two hours later.
Saturday, Oct 26, 2013 7-8am: A group of 16 from the Auckland branch of the New Zealand Alpine Club leave Tahurangi Lodge to climb Mt Taranaki, with six ascending via the north ridge, and 10, including Hiroki Ogawa and Nicole Sutton, via the more difficult east ridge.
Countdown to a tragedy
4.20pm: Dr Ogawa, Ms Sutton, John Salisbury and Kirsten Spencer decide to continue to the top when the others "bail" due to bad weather conditions and cold.
8-8.30pm: The group reach the top and lower themselves into the crater, where they pause for some food and rest before starting their descent.
9.46pm: Dr Ogawa texts Rowan Smith at the lodge telling him Ms Spencer had slipped and was injured, and Ms Sutton was hypothermic.
10pm: Mr Smith and another club member set off back up the mountain to try to meet them, while someone at the lodge calls 111.
12.27am: Mr Smith receives a text message from Dr Ogawa with GPS coordinates. They are close to the summit at 2318m.
12.31am: Dr Ogawa texts police, says Ms Sutton "in bad shape". "Can move a bit but very slow and cold. Not very safe to move far."
12.40am: Police text Dr Ogawa: "Search teams now on mountain. Keep warm and safe. We are coming. Hope to have helicopter soon with your coordinates. About one hour safely."
1am: Taranaki Alpine Cliff Rescue team leaves the lodge, coming within 150m of the GPS coordinates, but are forced back due to "horrific" weather.
1.10am Police text Dr Ogawa: "Winds too strong for helicopter. Teams on way to you on foot. Have already left Tahurangi Lodge. ETA an hour."
2.40am: Police communications contact Ruapehu Alpine Rescue Organisation for help.
3.15am: Call is made to the Royal New Zealand Air Force for assistance.
8.41am: Ms Sutton sends text: "Need help asap. Hiroki not good." Two minutes later: "Both hypothermia."
9am: Two rescue teams set off up the mountain.
5.45pm: Ms Sutton sends text: "Please rescue asap. Vis [visibility] OK up here. Hiroki in bad way. Don't think tonight will go well."
5.51pm: Ms Sutton texts: "Not sure if Hiroki will get through tonight. Vis [visibility] OK for heli[copter]."
12-12.30am: Two rescue teams head up the mountain, one comes within 100m before running out of rope and returning.
3am: A third team leaves the lodge.
7.30am: The third team of rescuers reach the stranded couple, to find Dr Ogawa already dead.
9.30am: Ms Sutton passes away in rescuer's arms.