High-risk warning on Ruapehu remains

THE volatile Mt Ruapehu remains a high risk as scientists are still unable to determine whether any eruptive activity occurred on Wednesday night.
The mountain struck the attention of Department of Conservation (DoC) and Geological and Nuclear Science (GNS) scientists after the Eastern Ruapehu Lahar Warning System (Erlaw) was activated at about 10.25pm by a volcanic earthquake measuring 2.8.
However, bad weather has, and still is, hampering their investigation to see what actually happened.
Both concede some activity occurred as a sensor was damaged in the event.
The Southern Ruapehu Lahar Planning Group (SRLPG) along with Doc and GNS met yesterday to discuss the triggering and how well their emergency management plan worked.
The SRLPG includes the Ruapehu District Council, Horizons Regional Council, Ministry of Civil Defence and Emergency Management (MCDEM) and police.
DoC Conservancy scientist Dr Harry Keys said it was still unclear whether a small volcanic eruption or lahar occurred.
"Due to bad weather we were unable to get an aerial view of either the crater lake or the Whangaehu River where the lahar would have flowed out of the crater lake on Thursday.
"However, further evidence we have seen (on Friday) suggests the likelihood of a small lahar having occurred is minimal," Dr Keys said.
"As a measure of safety DoC is maintaining the high risk warning we have in place for the summit area of Mt Ruapehu while a low risk warning is in place for the upper parts of the Whangaehu, Mangaturuturu and Whakapapaiti valleys."
DoC and GNS scientists would visit Crater Lake as soon as weather allowed, he said.
People were urged to avoid the Crater Lake area until DoC and GNS scientists have visited the area.
RDC Mayor Sue Morris said the unexpected "live" volcanic event provided the perfect run-up to the scheduled training exercise planned for later this month.
Dave Wakelin of DoC said the heavy snow fall on the mountain could rule out any trace of evidence as it had reached as low as the Kaimanawa Ranges.
Mt Ruapehu had been sitting at level 1 for about nine years as it was known to go through a number of "phases" until its bigger lahar event which could occur within two years.
"It's at a state of volcanic unrest and that's just the normal state of affairs."
Central district police operations manager Senior Sergeant Richard Smith said police were very pleased with the Lahar Emergency Management Plan (LEMP) and how it was enacted.
The sensor triggering saw police stop traffic on SH49 at Tangiwai and SH1 at the snow gate until the "stand down" was received.
"Due to the time of night only around eight trucks were held up for 20 minutes in Waiouru with only one car stopped at Tangiwai."
The next desktop exercise for the LEMP is planned for October 25.