It was not known why the man went around the barrier but low visibility at the time might have been a factor, Mr Smith said.
The man did not have a phone with him and the alarm was raised by his companions at about 4.30pm.
Searchers found his snowboard at the bottom of the bluff, and his car keys a little further down and managed to track his footprints in the snow, although time was not on their side.
"It was snowing quite heavily and [the footprints] were filling up, so it was a bit of a race against time."
The man was following the Whakapapanui Stream, which runs through the bottom of Skippers Canyon, downstream and had made it about two-thirds of the way down the mountain when the searchers found him just after 11pm.
Mr Smith says by this time the man was exhausted, cold and suffering hypothermia. It was snowing and the temperature would have been minus one or two degrees, he estimated.
"He had stopped but he was still standing. I think he was probably at the point where he was thinking about somewhere to stay the night."
Mr Smith says a lot of help was needed to get the man the rest of the way out to Whakapapa Village where an ambulance was waiting, with the group finally arriving about 1.30am.
"He was pretty knackered... he was dry-retching and couldn't stand up."
The man was taken to Taupo Hospital with hypothermia and a broken rib. He was discharged a few hours later.
Mr Smith says given the conditions and the man's exhaustion, he did not think he would have made it to Whakapapa Village on his own.
"I think we saved his life for sure."
Around 25 Ruapehu Alpine Rescue Organisation searchers were involved in the rescue, including ski patrollers from Whakapapa and Turoa, Ruapehu Alpine Lifts cat and skidoo operators, Hillary Outdoors instructors, police and St John.
