Austin Green, described as a "very good skier", was skiing alone off-piste in Shadow Basin when the accident occurred. The 17-year-old hit a rock. He also hurt his side and stomach in the crash.
He managed to take himself to the skifield’s medical centre and his father was called to meet him. When medics asked if he hit his head the youngster was not sure.
"One of them [medics] looked at his helmet and everyone took a sharp intake of breath," Mr Green said.
"There was a huge hole in it and a rock [was] still embedded in the helmet; going all the way through and just protruding on the inside."
Mr Green said it was a scary thought that "that could have been his head".
"It could have been a very different story if he had not been wearing his helmet."
Austin said the lack of blood kept him calm. The Wakatipu High School pupil suffered bruising to his side and was in pain. There were also concerns he might have had internal bleeding.
Mr Green said his son always wore a helmet. He had also skied from a young age and attended ski school through primary and secondary school.
"You need to be careful out there as even experienced skiers can get caught out.
"You might think a helmet is expensive but it really isn’t, and what price can you put on not having a head injury for the rest of your life or worse?"
Austin was skiing within the skifield boundary when the incident happened, just under the Shadow Basin chairlift on an ungroomed area.
His father spotted him just moments before the crash as he ascended the hill on the lift. He witnessed a snowboarder make a "nasty fall" but did not see Austin tumble.
Mr Green said it would not deter his son from picking up his skis and getting up the mountain.
"It was one of those days. A powder frenzy — people were excited about the snow. They take a few risks and maybe go a few places they maybe wouldn’t otherwise.
"The coverage is still a bit light on some places off-piste so you do have to be careful. Most people who do know those risks are sensible and take the right precautions.
"But there is a chance some people don’t understand. Those are the people I want to get the message out to."
While Austin was still a little sore and bruised, Mr Green said ‘‘he’ll be right’’ in a few days and did not need any further medical attention.
Ski area manager Ross Lawrence said he was aware of the incident and confirmed it was in an ungroomed section of the ski area.
"We are still looking for more snow cover and there are definitely still hazards people need to be aware of off groomed trails when they are out and about — it is a natural landscape. If they are going off-piste they need to be wary of that and make sure they are adequately equipped."
