Ruapehu blows

A climber was due to be operated on this morning after his legs were crushed by rocks in last night's eruption on Mt Ruapehu.
William Pike, a 22-year-old primary school teacher from Auckland, is in Waikato Hospital in intensive care in a serious condition with hypothermia and both legs crushed.
Scores of people fled from the mountain last night after the eruption, which shook the volcano about 8.20pm and was witnessed by airline pilots.
The volcanic blast destroyed out a monitoring hut near the crater lake, sending two muddy torrents down the skifields.
A covering of ash could be seen around the volcanic crater at the summit of the mountain this morning.
Mr Pike is a member of the Alpine Club and was in the Dome Valley Hut when a huge rock smashed through the roof and crushed his legs.
His parents Barry and Tracy say their son is a passionate climber.
"He lives to climb. He was in a place that he loved. He is a very conscientious climber and an incredibly active person," said Mrs Pike this morning.
Mr Pike was believed to have been in a hut with three companions when the rock smashed through. His companions were unable to move the rock and sought help.
A vehicle from the Whakapapa Ski Field was able to reach the hut and the injured man was then freed. He was then carried to a road where he was met by an ambulance.
The Taupo Lion Foundation rescue helicopter met the ambulance and flew Mr Pike to Taumarunui Hospital where he was treated and then airlifted to Waikato Hospital.
The black-tinged mountain remained off-limits today as authorities assessed the damage caused by last night's eruption and the risk of further activity.
The eruption caused the closure of highways around the mountain, stopped trains and closed the main trunk railway line and the evacuation of ski lodges.
A group of GNS and Department of Conservation scientists flew over the mountain at first light to take a look at the impact of the eruption, which occurred without any warning.
GNS volcanologist Brad Scott described the eruption as "small to moderate" - smaller than the eruptions of 1969 and 1975 but bigger than last October's.
"Impact craters", upt to 2 metres wide caused by debris hurled into the air were seen about 1.5km from the crater edge and a lot of water had pooled at the top of the volcano and then run off down the Whangaehu and Whakapapa glaciers, Mr Scott said.
The lahars (mud flows) created by the eruption had been minimal, reaching only a short distance down the mountain and not causing any damage on the skifields.
There was no lava in the eruption but the top of the mountain was blackened by mud and ash thrown out of the crater.
Mr Scott said the level of the crater lake had not changed with the eruption and he did not think there was any greater risk of a breach occurring in the crater rim. However, he did predict more murmurs from the mountain before it settled down again.
"Typically you'll have two or three smaller events over the next few days if this plays out like 1975."
Mr Scott said volcanologists were not "totally surprised" by the eruption, as the crater lake had been cooling down over the past few months.
"That's pretty much the perfect conditions for these 'blue skies' (without warning) eruptions to occur."
He described the eruption as steam-driven, rather than being caused by new lava coming into the volcano, as was the case in 1995 and 1996.
Mr Scott said it was not yet considered safe enough to send scientists up to the crater on foot to make assessments.
"There's no way that we'll be putting any staff up there at this time."
Public access roads on the mountain and both Turoa and Whakapapa skifields were closed today.
Skifield operator Ruapehu Alpine Lifts said it was taking "the prudent approach" in closing today and if there was no further volcanic activity in the next 24 hours, both skifields would be open tomorrow.