MT RUAPEHU ERUPTS

A CLIMBER'S legs have been crushed after boulders and water smashed through a Mt Ruapehu hut during an eruption.
Scientists hoped to learn more today about what caused Mount Ruapehu to erupt suddenly last night at 8.23pm. The eruption is believed to have lasted around 10 minutes and was accompanied by a seven-minute-long, 2.9 magnitude earthquake.
A plume of ash was sent about 4500m into the air and two lahars spilled down the mountain - one north across Whakapapa and the other east into the Whangaehu River, the same path as the March lahar.
The climber - William Pike - had been in Dome Shelter above the Crater Lake at the time of the eruption.
Mr Pike was pinned to the floor by a boulder which smashed through the door and roof of the shelter. The boulder was too big for the injured man's climbing companion, James Christie, to lift.
Mr Christie - followed the path of the lahar down the mountain to the Whakapapa Ski Field to get help.
A five-person rescue team from Ruapehu Alpine Lifts rescued Mr Pike from the hut before the Taupo-based Lion Foundation Rescue Helicopter flew him to Taumaranui Hospital.
From there, Mr Pike - an Auckland school teacher - was met by the Westpac Waikato Air Ambulance and transferred to Waikato Hospital.
The injured teacher was this morning in a serious condition in Waikato Hospital's emergency department where he was being treated for crushed legs and hypothermia. It was hoped he would be able to have surgery this morning.
The ash cloud prompted a Metservice warning for aircraft in Taupo, Rotorua and Whakatane regions to avoid the areas. Meanwhile, Department of Conservation and GNS Science staff were to meet early this morning to assess the volcanic activity and damage from the eruption.
Speaking to the Daily Post this morning GNS duty vulcanologist Craig Miller said there had been little activity overnight.
He said they hoped to learn more from flying over the mountain today and seeing the impact of the eruption and lahars. Mr Miller said until scientists saw the damage for themselves there was only so much they could interpret from instruments and witness reports.
Mr Miller said there had been several reports from ski field operators, as well as pilots who were flying above the mountain at the time.
He said vulcanologists believed the eruption was a "steam-driven eruption" - which comes from the hydrothermal rather than deeper down in the earth.
"We don't think there was any magmatic input".
Mr Miller said the eruption was similar to those that happened in 1969 and 1975, which also happened when the Crater Lake was cold.
He said there could still be some similar eruptions of a small scale but they would know a lot more after this morning's flight.
Mr Miller said there was nothing in the lead up to suggest an eruption was likely - although these type of eruptions usually came with "very little precursor activity".
One of Whakapapa's snow groomers Shane Buckingham described a wall of mud and debris a metre high sweep past him. After the eruption Iwikau Village was evacuated but the decision was reversed a short time later.
About 50 people were evacuated to the Bayview Chateau Tongariro with some spending the night there.
The lahars from last night's eruption were smaller than the one in March, which sent 1.3 million cubic metres of water and debris into the sea. The eruption closed highways and rail links around the mountain but they opened overnight.
Ruapehu District Council communications manager Paul Wheatcroft said he had spoken to one person in a ski hut who said he was outside and hadn't noticed a thing on the mountain.
Mr Wheatcroft said he had heard that the ski huts were all being evacuated. While he was unsure how many people were in the huts it was school holidays so they were likely to be crowded.