Ruapehu eruption, 1996
Image: Thorvaldur Thordarson, GNS Science | ©

Introduction

Find out about volcanic hazards in Tongariro National Park, how to reduce risk when visiting, and what to do in the event of an eruption.

Highlights

Tongariro National Park is an active volcanic area. Eruptions can occur with little or no warning. The closer you are to the Park’s active volcanic vents, the higher the risk you are exposed to.

A network of volcanic monitoring equipment and warning systems mitigate risk but cannot guarantee your personal safety. You are responsible for deciding the level of risk that is acceptable to you and planning your visit accordingly.

On this page:

Current status of volcanoes

Ruapehu volcano

Management stage: DOC Risk Management Stage B
GeoNet level: Volcanic Alert Level 1 - Minor Volcanic Unrest

Eruption likelihood is slightly elevated above normal levels. Stay out of the area 1.5 km from the centre of Te Wai ā-moe/Crater Lake.

More advice on how to reduce risk at Stage B

GNS have established that a body of magma is still present at relatively shallow depth in the volcano. It is roughly at the elevation of Whakapapa Village – magma normally sits at around sea level.

This body of magma has stopped progressing towards the surface. But, the shallow magma presence means a sudden resumption of activity, or sudden onset eruption, is more likely than the last time Ruapehu was at VAL 1.


Tongariro volcano

Management stage: DOC Risk Management Stage A
GeoNet level:
Volcanic Alert Level 0 - No Volcanic Unrest

We have no additional guidance at this time. 

Read advice for Tongariro


Ngāuruhoe volcano

Management stage: DOC Risk Management Stage A
GeoNet level:
Volcanic Alert Level 0 - No Volcanic Unrest

We have no additional guidance at this time. 

Read advice for Ngāuruhoe (See ‘Reduce risk at Tongariro’)

What to do before you go

  • Check the current status of the volcanoes in the park and follow the risk reduction advice at appropriate DOC Risk Management Stage (see above). 
  • Know where the volcanic hazards zones are.
  • Check the webpages of DOC tracks you plan to use for any closures and additional safety advice.
  • Know the eruption advice for Whakapapa Ski Area or Whakapapa Village if visiting these areas.
  • Consider whether you're comfortable with the volcanic risk associated with your trip. If you are not comfortable, visit somewhere outside the Park's volcanic hazard zones.

How to stay safe in an eruption

  • Move immediately away from the eruption site, staying out of valleys
  • If you’re in a valley, move sideways to higher ground (a ridge top) – a fast moving volcanic mud flow like a flash flood (a ‘lahar’) is possible.
  • If you see flying rocks, or a steam and ash cloud coming towards you, take shelter behind a bank or ridge and cover your head with your pack.
  • If you are in Whakapapa Ski Area or Village, follow the below instructions 

Eruption advice for Whakapapa Ski Area and Whakapapa Village

Lahars are the main volcanic hazard at Ruapehu. There are lahar warning systems that warn visitors when an eruption has occurred, and a lahar is possible. Sirens and voice messages will sound in specific areas to warn visitors.

How to reduce risk at Ruapehu


Lahar deposit on Ruapehu, 1996

Eruption hazards

The Summit Hazard Zone on Ruapehu is a 3 km radius around Te Wai ā-moe/Crater Lake, which fills the vent of Ruapehu.

Flying rocks, fast-moving clouds of steam and hot ash can occur during eruptions of Ruapehu. These are the most hazardous within the Summit Hazard Zone.

The main volcanic hazard on Ruapehu is lahar. Lahars are a fast-moving volcanic mud flow like a flash flood. They occur during eruptions when water in the lake is ejected and flows at speed down valleys as a flash flood – mixing with ash, rocks and snow on the way down.

There are multiple lahar paths through Whakapapa Ski Area, where a lahar warning system operates. Lahars can also occur when volcanic debris on the volcano’s slopes is remobilised during heavy rain.

Lahars can have impact beyond the Summit Hazard Zone – large events have travelled well beyond the slopes of the volcano.

Reducing risk at each Risk Management Stage on Ruapehu

At all activity levels, the closer you are to Te Wai ā-moe/Crater Lake and the longer you stay, the higher the risk you are exposed to. Eruptions can occur at any time, with little or no warning.

See the Current Status section for Tongariro National Park volcanoes’ present activity. 

Click the DOC's Risk Management Stage and Volcanic Alert Level below to read our advice on how to reduce the risk.

How to reduce risk at Tongariro

Tongariro and Ngāuruhoe are currently at GeoNet Volcanic Alert Level 0 and have no volcanic unrest. Due to the current lack of activity, there is no additional risk reduction advice for visitors at Tongariro.

The Tongariro Alpine Crossing and Tongariro Northern Circuit both pass through Tongariro's volcanic hazard zone. If GeoNet Volcanic Alert Level (VAL) increases at either the Tongariro and Ngāuruhoe volcanoes, there will be track or track section closures. 

The Tongariro Hazard Zone is a 3 km radius from each of the three active vents of Mt Tongariro – Te Maari, Red Crater and Ngāuruhoe. Reduce your risk before you go by reviewing the:

How we manage risk at each volcanic alert level

We manage volcanic risk on the Tongariro Alpine Crossing and Tongariro Northern Circuit by identifying closure points based on the GeoNet Volcanic Alert Level (VAL) at the Tongariro and Ngāuruhoe volcaneos.

Tongariro and Ngāuruhoe typically sit at VAL 0 (no volcanic unrest). When the VAL increases to 1 (minor volcanic unrest) at either volcano, we close tracks and assess.

The length of this initial VAL 1 closure period is dictated by the data available, risk assessments and input from GNS and/or other subject matter experts. If DOC is confident that the probability of eruption is low, and the level of risk is tolerable, then the track is reopened.

At VAL 2 and above, the track is closed until the activity has deescalated to VAL 1 or VAL 0. Again, the assessment to reopen would involve risk assessments and expert input.

Eruption hazards

The three vents at Tongariro have all been active within the last 100 years. The most recent eruption occurred from Te Maari in 2012.

Flying rocks (ballistics) and fast-moving clouds of steam and hot ash are the main volcanic hazards on Tongariro.

Even when the tracks are open, some volcanic risk is present as eruptions can occur at any time. If you are uncomfortable with this risk, choose a different track outside of volcanic hazard zones.

Read more on how to stay safe in an eruption.


New Zealand Volcanic Alert Levels

The system evaluates the current level of volcanic unrest or eruption of the volcanoes in Tongariro National Park. The New Zealand Volcanic Alert Level is set by GeoNet, based on volcano monitoring data from the Park. There are six Volcanic Alert Levels, ranging from no volcanic unrest, through two levels of volcanic unrest, to three levels of volcanic eruption.

For more information and to see the current Volcanic Alert Levels for the volcanoes of Tongariro National Park, see Volcanic Alert Levels (GeoNet website)

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