Rescuers are stressing the importance of personal locator beacons following an avalanche near Aoraki/Mt Cook this morning that struck a climbing party of three, killing two mountain guides.
Adventurer Jo Morgan, wife of businessman and philanthropist Gareth Moran, miraculously survived after being buried beneath the avalanche on Mt Hicks for 30 minutes before digging herself out of the snow. Her two climbing partners died at the scene.
Morgan had a personal locator beacon (PLB) on her, which she activated while buried, before also managing to speak to rescuers on the phone after digging herself out.
Rescue Coordination Centre NZ senior search and rescue officer Neville Blakemore said Morgan's actions had likely saved her life.
"When carrying a PLB it is important people keep them accessible, exactly as she did.
"There is no point having it buried at the bottom of your pack, in case you are in an accident and can't reach it. If she had not had it with her we would not have known she was in trouble until much later.
"She was experienced, had been out climbing a lot before and was very sensible, as were those she was climbing with."
Both victims were male guides, aged in their 50s, understood to be originally from Germany.
The trio headed off at 2am this morning for the top of Mt Hicks, which they reached.
But on the way down on the southwest ridge, the avalanche engulfed them.
Morgan activated her PLB at about 6am - about half an hour after the avalanche struck.
The PLB sent a digital signal to a satellite, which was sent back to Earth and processed at a regional rescue hub in Australia, before making its way to New Zealand's Rescue Coordination Centre, based in Wellington.
Blakemore said this all happened in seconds, with initially general information coming through that a PLB had been activated in New Zealand's area of responsibility, which extended into the Pacific Ocean and even down to Antarctica.
Morgan's beacon was registered with the rescue centre, so they knew who it belonged to and had contact details, Blakemore said.
The beacon also had GPS capability, meaning her coordinates came through to the centre as well.
Non-GPS devices also provided location information, but this could take about five to 10 minutes to be processed and was less accurate, Blakemore said.
"As it was registered to Morgan we phoned her when we received the signal, but she was buried under the snow then so we couldn't reach her. So then we phoned her next of kin, her husband, who explained she was out climbing in the Aoraki Mt Cook area."
Once they had that information the rescue centre was able to activate rescue teams in Mt Cook Village and Christchurch.
About 45 minutes after Morgan activated her PLB, the rescuers managed to speak to her on her phone, after she had managed to dig herself out of the snow.
Rescuers arriving on the scene performed CPR on both guides. But Area Commander Inspector Dave Gaskin said one of them may have been killed almost instantly.
It was understood that Morgan "swum through the avalanche", which Gaskin said was a "pretty standard technique" to stay close to the surface.
"When the avalanche ended, she's had one arm or both arms out of the snow and managed to get out of the snow and set off the alarm," he said.
Gaskin said it was an isolated, wilderness area but they were well-equipped and "just unlucky in the situation they found themselves in".
"They had all the gear," he said.
Avalanches were a "constant threat" in the Mt Cook/Aoraki region, Gaskin said, and even more so with the recent bad weather, which had seen new snow sitting on ice.
Blakemore said personal locator beacons were becoming more common, and in many instances could save lives.
"They are extremely important, as many areas people go there is no cellphone coverage.
"More and more people are using them - in the sea, in the air, on land, and anecdotally we are probably dealing with about three rescues a day where they have been used."
Blakemore said he estimated dozens of people were saved each year because of their PLBs.
"In one instance we had a tramper who had become delirious from the cold, but managed to set off his PLB. He was rescued but was suffering severe hypothermia, and likely would not have lasted too much longer. These things save lives."
Australian hunter Joe Prusac credited his PLB with saving his life, after he fell 40m off a cliff in the Kaweka Ranges, breaking his neck and spending 14 hours in the freezing cold.
Serial litigator Graham McCready also said his PLB saved his life after he got into strife on a popular New Zealand cycle trail this month.