Wellington - A massive lahar, or volcanic mudflow, swept
thousands of tonnes of rock-filled water harmlessly down a New
Zealand mountainside on Sunday, reviving memories of a similar event
54 years ago which killed 151 people when a bridge was swept away
shortly before a train passed over it.
Alarms and safety systems installed on 2,797-metre high Mount
Ruapehu following the disaster on Christmas Eve 1953 worked
perfectly, allowing roads and the railway track to be closed
immediately the volcano's steaming crater lake burst its banks.
'The lahar travelled down the path as predicted, and the early
warning response system worked exactly as planned,' said Conservation
Minister Chris Carter.
Civil Defence Minister Rick Barker said bad weather over the
weekend had fortuitously kept hikers and climbers off the mountain,
which is the North Island's highest peak.
Nobody was hurt and damage was limited, ironically, to a memorial
to those who died in the 1953 tragedy, and a hikers' footbridge as
the lahar, which uprooted trees and boulders in 3 to 4-metre high
waves moving at more than 20 kilometres an hour, made its way down
the mountain and out to the Tasman Sea.
The lahar had long been expected and officials were delighted
that, confined by a new stopbank, it kept to its expected course down
the mountain into the Whangaehu River valley and past the village of
Tangiwai, near the rail bridge, without harming anybody.
Police, alerted by a series of automatic alarms monitoring the
crater lake's temperature and level, closed all roads in the area,
including the highway between the capital Wellington and the
country's biggest city Auckland, and stopped trains on the main trunk
line, stranding hundreds of motorists and rail passengers for several
hours.
Scientists had been closely monitoring the 17-hectare crater lake,
which sits about 250 metres below the summit of Mount Ruapehu, since
January when seeping water threatened to sweep away the rim.
Weathermen said extremely heavy rain had fallen on the mountain
for more than three hours which probably accounted for the rising
lake level which breached the dam walls.
A Department of Conservation spokesman described the lahar as
'moderate.'
The National Crisis Centre in Wellington was activated
and officials said the lahar emergency response plan had worked as
expected.
It was the first real test of the safety measures and Conservation
Minister Carter said, 'I am pleased that we now have a robust system
in place to manage this kind of natural event - and to do so with a
great degree of advance warning, with the least amount of damage to
people and property is the ideal situation.'
© 2007 dpa - Deutsche Presse-Agentur 
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