Civil Defence cancels volcano threat alert

UPDATE: Civil Defence has cancelled its volcano threat alert. An update this afternoon reads:

The latest assessment from GNS Science is that eruption activity has subsided. White steam clouds were observed at the historically active Te Maari craters area. There is no ash being produced from the volcano presently. There have been no lahars or pyroclastic flows or lava flows.

It is too early to predict the next series of events, but GNS Science expects heightened activity may continue for several weeks. There are likely to be specific signals of future magma movement beneath the volcano and GNS Science continues to monitor the situation through the GeoNet volcano-seismic network of instruments.

As with any volcano, an eruption could occur at Tongariro at any time with little or no warning and there is an elevated level of risk, particularly on the northern slopes and valleys of the mountain. The volcanic alert level for Tongariro volcano remains at alert level 2. [See threat level table end of story]

Therefore, we advise a continued precautionary approach towards activities in the vicinity of the Tongariro volcano, to stay clear of restricted areas and to check with Department of Conservation on status of roads and National Park access.

UPDATE / 11am:

Local aviation operators are flying as normal after last night’s eruption of Mt Tongariro.

Scenic flight operator HeliPro took GNS scientists and department of conservation staff to survey the area earlier today.

Taupo-based pilot Toby Clark told NBR ONLINE the plume of steam rises no higher than 8000 feet (2440m)and it is drifting east, away from the region.

“There’s only been one event that we can see and the GNS and DOC guys I had with me couldn’t see directly into where it was coming from because of the cloud.

"But there is a plume coming up through the cloud at about 6000 feet (1800m) and it’s no higher than 8000.

"There’s a lot of ash on the ground around the edge of Lake Rotoaira, just east of Tongariro, otherwise it’s all very low stress.”

He also expects Air New Zealand won’t take long to resume flights as usual “because they’ll be able to fly well above the plume”.

Auckland Airport says 13 domestic arrivals have been delayed, 10 have been cancelled, while nine departures have been delayed and 10 cancelled.

Just east of the national park, Tongariro Aviation operates from Turangi and its manager says the area is clear of ash and his company is operating as usual.

Meanwhile, Horizons regional council isn’t expecting Tongariro residents to be significantly impacted because the ash is moving away from the region.

But emergency manager Shane Bayley is advising people living downwind to disconnect their rain water tanks.

“Ash can find its way into rain water tanks and contaminate supplies. We advise residents in the affected areas to disconnect these if it is safe for them to do so."

Less than three weeks ago, GNS scientists lifted Mt Tongariro's volcanic alert status from zero to level one, following a sudden increase in volcanic activity.

UPDATE / 8am:

Mt Tongariro erupted last night at 11.50, with reports of loud explosions, glowing rocks flying from the mountain and ash falling as far away as Napier.

Air New Zealand is expecting delays and cancellations to its flights throughout the North Island.

Click here for a large version of the erruption photo.

Flights east of Mt Tongariro, including Gisborne, Rotorua, Taupo, Napier and Palmerston North, are likely to be affected as a result of the eruption – the first since 1897.

Air New Zealand is working closely with the Civil Aviation Authority, the MetService and other authorities to keep up to date with ash movement and the local forecast.

Air New Zealand airline operations and safety general manager and chief pilot, captain David Morgan, says the airline is working with the authorities to make safe changes to flight routes to ensure aircraft remain clear of any ash and keep providing a safe service to the travelling public.

“We will not fly through ash and are constantly taking guidance to ensure we can continue to carry passengers where safe routes and altitudes are available.”

Air New Zealand says its website will be constantly updated throughout the day with modified arrival and departure information.

Reports of the extent of the eruption remain sketchy.

The eruption appears to have happened at Te Mari Craters, close to the Ketetahi Hot Springs on the northern side of the mountain, catching GNS by surprise.

The government agency says the eruption was small scale, and lasted around five or six minutes.

A layer of ash around 3mm thick fell on the Desert Road, which was  closed as a precaution. 

One man told police he saw  flame-like explosions and a cloud of ash coming from "a new hole in the side of the mountain".

Truck driver Bryn Rodda told Radio NZ he saw a large cloud rising from the mountain with orange flashes. The cloud was so thick he had to slow down considerably as he passed through the cloud,

More volcanic activity likely
A GNS duty volcanoligist told TV3's Firstline there are no immediate signs of futher volcanic activity but "the fact the volcano has woken up and had this eruption definitely indicates there could be further activity".

"We anticipate more activity now that the craters have broken through."

No evacuation ordered
In its third update, issued at 4.22am, Civil Defence said it had not ordered any evacuation and that the National Crises Management Centre has not been activated.

Civil Defence noted there has been some self-evacuation by concerned local residents.

GNS duty volcanologist Michael Rosenberg told Radio NZ some locals had left their houses on the southern shores of Lake Rotoaira because they were so alarmed by what they saw. 

Residents told GNS of hearing several loud explosions, lightning and plumes of smoke.

GNS has raised the threat level for Mt Tongariro from one to two on its five-point scale (see table below).

Civil Defence has issued a potential threat advisory covering the following central North Island areas:

• Waikato
• Hawke's Bay
• Gisborne
• Manawatu-Whanganui
• Bay of Plenty
• Taranaki

It has scaled back from an earlier advisory telling residents of those areas to stay indoors.

People living in the immediate area are asked to stay indoors and keep windows and doors shut.

Flight disruption unlikely
The Aviation Colour Code has been raised from yellow to red, closing local airspace for an eight-mile radius around the eruption.

But air travel is not likely to be disrupted too heavily as aircraft will adjust their routes to avoid ash cloud danger.

MetService expects the ash cloud to linger around the central North Island until Tuesday evening.

Road closures
The Desert Road section of State Highway 1 and part of State Highway 46 have been closed due to a covering of ash.

Regional and local civil defence emergency management is monitoring the situation. Local council CDEM, police and department of conservation are currently meeting in Taupo.

GNS has a webcam aimed at Mt Tongariro, which may reveal more as daylight breaks. Follow it here.

VOLCANO THREAT LEVELS

0 Typical background surface activity; seismicity, deformation and heat flow at low levels. Usual dormant, or quiescent state.

1 Apparent seismic, geodetic, thermal or other unrest indicators. Initial signs of possible volcano unrest. No eruption threat.

2 Increase in number or intensity of unrest indicators (seismicity, deformation, heat flow, etc). Confirmation of volcano unrest. Eruption threat.

3 Minor steam eruptions. High-increasing trends of unrest indicators, significant effects on volcano, possibly beyond. Minor eruptions commenced. Real possibility of hazardous eruptions.

4 Eruption of new magma. Sustained high levels of unrest indicators, significant effects beyond volcano. Hazardous local eruption in progress. Large-scale eruption now possible.

5 Destruction with major damage beyond active volcano. Significant risk over wider areas. Large hazardous volcanic eruption in progress.