He called rescue services as he made his way down the slope to find his friend, a Christchurch-based engineering consultant, beginning CPR when he found his pack and his body.
Mr Vinton-Boot died at the scene, and the coroner concluded there was nothing more rescue services could have done to save his life.
The pair had an avalanche beacon and an ice axe, but it was concluded they would not have saved him.
He died of multiple traumatic injuries, including a substantial head injury.
Despite being experienced climbers, with Mr Vinton-Boot a former New Zealand Mountaineer of the Year, the pair appeared to have ignored some of the risks associated with their climb that day, Coroner David Crerar said.
"The traverse by Jamie and Steven was of slopes which were, for them, well within their capabilities and of low risk," coroner Crerar said.
"In retrospect, Jamie and Steven could have noted the significant consequences of a fall from the Queens Way."
The two friends had not discussed whether the route was exposed to avalanches, and had not discussed the conditions since they left the carpark, Mr Fortune's evidence to police showed.
They had chosen not to be roped together, and did not 'belay' - fixing a rope around rocks or other objects as a safety measure - the route at the more dangerous sections.
A Back Country Avalanche Advisory had been upgraded early that morning to "moderate to considerable".
Giving evidence to the inquest, senior guide Geoffrey Wayatt, director of skifield safety for the Cardrona Alpine Resort, said while he did not consider the two men's actions as reckless, a more prudent approach could have been taken had they observed avalanche control works or checked the updated avalanche advisory.
"Guide Wayatt recognised that Steven and Jamie were very capable and experienced mountaineers, but that, in his opinion, they appeared unaware of, or they ignored, the possibility of the significant avalanche danger on the morning," coroner Crerar said.
"They did not fully consider the new snowfall, steep access terrain and avalanche implications when they were traversing the steep slopes of the Queens Drive."
Coroner Crerar issued three recommendations, advising alpine climbers to gain an increased awareness of avalanche terrain, the risks and the consequences of being caught in an avalanche. He advised a best practice recommendation for climbers to carry beacons, probes and shovels when in avalanche prone terrain, and that his findings should be sent to all mountaineering and alpine clubs so climbers were aware of the risks.
