Man struck by 100kg boulder on Mount Ngauruhoe

In a risky rescue, a member of the Ruapehu Alpine Rescue team was winched down to the rim of the volcano's crater. Photo / Supplied

A man in his mid-twenties had a lucky escape today when he was struck by a boulder estimated to weigh up to 100kg on Mt Ngauruhoe in the central North Island.

The man was just below the summit at about 2200m when he was hit, injuring his legs.

In a challenging rescue, a member of the Ruapehu Alpine Rescue Organisation (RARO) was lowered down by helicopter to the rim of the volcano's crater.

Mt Ngauruhoe is an active volcano in Tongariro National Park and is 2291m high.

In high temperatures and wind, the RARO member scrambled about 60m further down to where the man was lying.

A long line - about 34 metres in length - was then hooked onto the helicopter, which hovered above the man before the rope was lowered down.

The boulder victim was wrapped in a rescue stretcher bag and along with the RARO member was picked up off the side of the mountain and flown on the long line to a staging area at Soda Springs, about 900m below where he was hit.

From there paramedics tended to his injuries before the Taupo-based Greenlea Rescue helicopter flew him to Rotorua Hospital.

Greenlea Rescue Helicopter was first alerted about 12.30pm and the operation lasted about three and a half hours in total.

Rescuers tend to the injured man on Mt Ngauruhoe. Photo / Supplied

Greenlea base manager Nat Every was the pilot for the rescue and said it was challenging because of high temperatures, the high altitude and changing wind conditions.

"The wind conditions today were extremely variable, every single place we landed, the wind was coming from a different direction," he told the Herald. "It's quite gusty at times and also the temperature was very high."

He said the two things that helicopters do not like are heat and height and today's rescue had both.

"Hot and high are not good for a helicopter because it ends up being a very high density altitude. Basically, you're effectively operating at 7300-odd feet, but as far as the helicopter was concerned, it was more like about 8500 feet just because it was super hot up there..."

Mr Every said his rescue helicopter team have been called for similar incidents in the past, where people have been hit by boulders on Mt Ngauruhoe. This was the first one this year, however.

"Those things happen from time to time. The problem with climbing up Mt Ngauruhoe is the route up the mountain and the route down the mountain are not too far offset from each other and if someone dislodges a boulder, obviously it's a danger to all those who are below them."

He said the chances of getting struck by a boulder increase the further you are down the mountain because there are more people above you.

"Which is just this unfortunate chap's luck - to be struck by a boulder right at the top of the mountain, basically."

Mr Every said the mountain was as busy today as he had ever seen it in five years.