The helicopter wreckage on Fox Glacier. Photo / NZ Police
"The site is near the top of the glacier, it's all ice, it's not level and there are blocks of ice as big as buildings with crevasses between them," says Inspector John Canning.
Bad weather at the Fox Glacier helicopter crash site may prevent investigators from examining the crash site over the next two days.
Transport Accident Investigation Commission (TAIC) spokesman Peter Northcote said deteriorating weather was threatening to slow its site investigation into yesterday's crash.
"Weather conditions stopped on-site operations this afternoon and are forecast to be unfavourable on Monday and Tuesday," he said.
Inspector John Canning said deteriorating weather meant operations on the glacier were likely to be on hold until at least Wednesday.
A search and rescue team in a NZCC Rescue Helicopter recovered three of the victims this morning during a brief lull in the bad weather that has beset the area.
The victims were winched aboard the helicopter, which was unable to land.
Mr Canning said the recovery was a technically challenging task which called for specialist skills in an unforgiving environment.
"The site is near the top of the glacier, it's all ice, it's not level and there are blocks of ice as big as buildings with crevasses between them," he said.
"There will be danger in getting teams into the area and traversing the area. While we're determined to return these people to their families, this will be a complex and technical task with an emphasis on the safety of those involved."
Mr Canning said alpine cliff rescue teams from Mount Cook and Franz Josef, as well as disaster victim identification teams, were part of the operation.
"It's a complex scene but there are some unique skill sets coming into play."
Mr Northcote said an investigator was able to survey and photograph the wreckage this morning. That would help with planning the on-site physical examination and removal of the wreckage, he said.
TAIC engineering expertise was also being used to plan how best to secure some pieces of wreckage while victim recovery work took place nearby.
"The visible wreckage is lying in heavily crevassed steep terrain about the size of a rugby field, and alpine cliff rescue staff assistance will be required for any on-scene work," Mr Northcote said.
"The commission and police are commissioning a commercial photography drone survey of the accident area, and this will take place when weather and other on-site operations allow.
"While on-site work is suspended the investigation team is focused on gathering documentary evidence, working with the operating company, and starting formal interviews."
Mr Northcote said agencies in France and the United States - where the aircraft and engine were made - had been invited to take part in the inquiry, as was the international convention.
"The United Kingdom and Australia have also been invited to appoint a representative due to their nationals having been passengers," he said.
The commission has a team of four in Fox Glacier with other resources on stand-by if required.
A drone is scheduled to fly above Fox Glacier to gather information on the wreckage and it is expected that a helicopter will be used to haul the wrecked machine out of the crevasse where it is wedged and lift it off the glacier.
Seven people - including pilot Mitch Gameren, two Australians and four British nationals - died in the crash of the Alpine Adventures tourist flight shortly before 11am yesterday.
Mr Northcote says the method of removing the crashed helicopter will "depend on the integrity of the parts of the wreckage when we actually get to be able to look at them close up".
"There are a range of aircraft types available, helicopter types, and methods that we could use, but it's too early to say what those might be.
"There are a couple of things that have to happen first. The first priority is the removal of the victims. The next priority is that the commission with the police are commissioning a commercial drone to do an aerial survey of the wreckage site before any significant pieces of wreckage are removed.
"That will take place over the next couple of days, weather permitting. Operations have ceased on the glacier this afternoon because of weather and it's looking not that flash tomorrow and potentially the day after.
"An investigator flew over the scene today and recorded it photographically. The scene is a very difficult one, heavily crevassed and snow and ice, and much of the wreckage is in a crevasse or buried."
The surface of the glacier around the wreckage site is steep in places and investigation staff will, for their own safety, in many places need to be attached by climbing rope to alpine rescue team members.
TAIC has a team of four deployed to Fox Glacier, including two investigators with helicopter pilot and engineering expertise, a consulting helicopter engineering expert, and a liaison and logistics manager.
The crash occurred between the centre of the glacier and its south-western edge at about 760m above sea level. The glacier is about 900m wide at that point.
Prime Minister John Key said the crash was "obviously very tragic", and he had passed his condolences for the loss of the Australians' lives to Australian Prime Minister Malcolm Turnbull when he met him last night.
Asked about any effect on visitor numbers, Mr Key, also Minister of Tourism, said he did not think it would put people off coming here, or undertaking adventure tourism activities.
"Most people are aware there is a degree of risk when you get in a helicopter. But, having said that, there needs to be a full investigation. We need to understand whether it was the weather that caused this issue."
Rob Jewell, chairman of Glacier Country Tourism, said this afternoon the alpine cliff rescue team and local search and rescue team were still involved in the recovery operation.
Mr Jewell believed one of one of the helicopter companies was helping with the operation earlier today.
"My understanding is that that's since stopped due to the weather."
Mr Jewell said everybody in the community was doing as much as possible to help out.
The local cafe, he said, was providing refreshments to people involved in the operation.
"It's a small community so everyone pitches in ... to make this as easy as possible."
Staff at some local helicopter operators, clearly upset, did not want to talk at length.
Earlier today, Alpine Adventures spokesman Mike Nolan said dismal weather hampered progress this morning and it could be days before families had closure.
"The weather is certainly hampering efforts. It looks like inclement weather for a further two or three days unfortunately. But hopefully there are some breaks in between where they can make progress - but at this stage it's really slow."