Rescue pilot Dan McPherson confirmed one person had died. He said a group was in the area heli-skiing when the avalanche happened.
A Herald photographer on the scene said police and other rescue staff took time to speak to witnesses while the heli-skiers loaded their equipment into their car. They left for the heliski base about 3pm, he said
A spokesman for GHC Aviation, which operates the air rescue service, told the Herald the Rescue Co-ordination Centre (RCCNZ) notified them of a possible avalanche or mudslide at 12.18pm.
The reported location of the avalanche, just south of Mt Arrowsmith, is about 46km west of Mt Hutt and about 130km west of Christchurch.
The Avalanche Advisory, owned and operated by the Mountain Safety Council, issues avalanche advisories for the public in 13 alpine regions, but not the Arrowsmith area.
‘Conservative decision-making essential’ – Mountain Safety Council
Earlier this month, the Mountain Safety Council urged skiers, snowboarders and climbers to check avalanche warnings before heading out.
Following heavy snowfall during the first week of September, the Mountain Safety Council issued avalanche warnings to remain in place for parts of the South Island.
There was a high risk of avalanches for Ōhau in the Mackenzie Basin where there are “very dangerous avalanche conditions” and travel in “avalanche terrain” was not recommended”.
Considerable avalanche risks remained for Arthur’s Pass, Aoraki Mt Cook, Two Thumbs, Queenstown, Wānaka, Fiordland and Aspiring, as well as Tongariro in the centre of the North Island.
There are “dangerous conditions” in these locations and “conservative decision-making is essential,” the council said.
Mountain Safety Council chief executive Mike Daisley told Newstalk ZB people should not travel in areas with avalanche warnings andshould stay inbound and within ski fields.
“Be really clear that you have the skills and knowledge to move yourself out of avalanche paths.
“It doesn’t mean people can’t go into the snow areas. It’s particularly important to know that if you are in a skifield area you are protected with professional ski and avalanche management.
“These warnings exist for people outside those ski fields.”
He pointed to the large dumping of snow much of the lower half of the South Island had experienced during the past few days for the increased avalanche risks.
He said things normally slow down at this time of year, but, during the past couple of winters, there have been some late snow dumpings.