At the bottom of the mountain two fire sirens sounded, one in Ohakune and the other in nearby Raetihi - the first inkling of the tragedy unfolding above the townships.
Minutes earlier a bus loaded with skiers hurtled out of control into a roadside barrier and rolled, causing fatal injuries to 11-year-old Auckland schoolgirl Hannah Francis.
As volunteer firefighters for two local brigades suited up, a father searched frantically for his daughter among the carnage at the 9km mark of Ohakune Mountain Rd.
At the same time a group of young friends returning from a morning's skiing at Tūroa in their car happened upon the horrific scene.
They, the first responders from Ohakune and Raetihi, St John medics from the mountain and a group of doctors on a ski trip, converged on the crash scene, calling 111, tending to the injured and setting up a makeshift triage area.
What they were confronted with was a mangled mess. The bus lay crumpled on its left side, the engine emitting smoke and the rear of the shuttle peeled back like the lid of a sardine can.
Clothing and ski gear were strewn across the road.
Nineteen passengers had been injured; some were able to walk, dazed and with bloody faces, cuts and grazes while others suffered broken bones and sprains.
The driver was thrown through the windscreen on impact, surviving with minor injuries that required a short hospital stay.
But Hannah's were the most severe. As quickly as possible the Glen Eden Intermediate pupil was loaded into a rescue helicopter and airlifted to hospital.
Tragically, she died en route.
Hours earlier Matt Francis had been enjoying a trip to Mt Ruapehu with Hannah and her stepbrother.
Just before 2.30pm last Saturday, the trio boarded a Ruapehu Alpine Lifts Mitsubishi Fuso shuttle bus.
Along with 27 other passengers the family were being driven down the mountain to Ohakune when the brakes on the bus appeared to fail.
Passenger Fenella Murphy was sitting four rows behind the bus driver with girlfriend Aleisha Cope.
The pair noticed the bus picking up speed on a straight, downward section of the road.
"The first sound we heard was this honking noise, like someone tooting the horn for a long time," Murphy said.
"Then we heard the driver panicking, and every time he stepped on the brake, there was a sort of gushing of air - we were starting to realise what was happening after that."
Amid the confusion children were moved to the back of the bus and those with helmets put them on.
"They were worried about going through the windscreen if we did have an impact, and because there were no seatbelts."
One man opened the back door and leapt out of the bus.
"People were shouting [at the driver]. Things like 'use the gears'. He wasn't saying anything, he was trying his hardest to keep the bus on the road."
As the bus began swerving erratically Murphy closed her eyes.
"When it initially hit the bridge barrier there was a big shudder. Then when we rolled, it happened very fast, so when we landed I had been thrown to the left of the bus."
The group ripped off the bus windscreen to make an exit for passengers while Cosgrove ran to the back of the bus and was confronted by an injured and bloodied passenger running toward her.
"All I could hear was a guy running at me screaming."
He collapsed on her. Blood poured from the man's head but he was more concerned about his wife who was still inside the bus.
As Cosgrove tended to his wound other motorists stopped to help including a group of doctors on a ski trip.
St John Ambulance staff arrived from Tūroa along with police and the Ohakune and Raetihi fire brigades.
Cosgrove grabbed snowboards for the injured to lie on and sat with one man until he was taken away in an ambulance.
"It was almost surreal because you don't have time to be scared. Everything was just done on adrenaline really.
"It wasn't until later on that you think about how scary it is."
Ohakune Volunteer Fire Brigade chief fire officer Keith Watson said on Facebook it had been a tough few days but he was lucky to be part of a great team.
"It was a difficult death for them," Watson later told the Weekend Herald.
Many of the first responders were also parents.
An Ohakune resident said the small town of 1000 and neighbouring Raetihi were reeling from the fatality.
A rāhui, or temporary tapu, was announced during a second blessing at the site on Sunday, by Uenuku Charitable Trust chairman Aiden Gilbert.
In Māori culture the rahui restricts access for three days but Gilbert said it was also about acknowledging the catastrophic event, and recognising the spiritual connection of tangata whenua to Mt Ruapehu.
"As Māori we have a very special connection to this place. There's been a ripple in the wairua [soul] of the maunga [mountain]."
Owhango Motors co-owner and mechanic Dave Edhouse services many of the commercial vehicles on the Whakapapa side of the mountain before they go for a Certificate of Fitness.
He said there were a number of complicated reasons that could have led to brake failure on the bus, but he had faith in the police Commercial Vehicle Safety Team to establish the cause.
Ruapehu District Council mayor Don Cameron said the three main bus operators in the region, RAL, Dempsey Buses and Roam Aotearoa, have been asked to check their fleets.
The 1994 Fuso bus that crashed had a 277,885km odometer reading, not high by commercial vehicle standards, and a current Certificate of Fitness.
RAL voluntarily suspended its bus operations after an urgent audit by police and New Zealand Transport Agency of the 12-strong fleet.
Roam bus operator Terry Steven said today would be the test of public confidence in the skifield and surrounding tourism operators, whether tourists returned.
"We've definitely had people ask about 'Are the brakes okay?'."
He said buses had a dual braking system on top of the exhaust brake, similar to an engine brake in a truck.
There would be a debrief between police, the council, Department of Conservation with issues concessions, and bus operators next week.