The Manawatū-Whanganui Region encompasses portions of Tongariro National Park and the North Island Volcanic Plateau, home to three active cone volcanoes - Ruapehu, Tongariro and Ngāuruhoe.
These maunga (mountains) are recognised for their geological dynamism and their cultural significance; they are regarded as tūpuna (ancestral entities) possessing mana (power) and mauri (life force). Planning for the risks posed by volcanic activity recognises this duality and seeks to integrate Western science and mātauranga Māori. A key part of this planning is the Central Plateau Volcanic Advisory Group (CPVAG), which you can learn more about on the About Us page.
You can head to the Department of Conservation website to find out about the current volcanic risk in Tongariro National Park.
Volcanic activity may manifest through a range of hazardous processes and physical phenomena, including but not limited to:
- Atmospheric particulate deposition (ash fall), with varied effects in nearby and distant locations.
- Pyroclastic density currents and ballistic ejecta - predominantly in nearby locations.
- Lahar (volcanic debris-flow) events - effects both nearby and along river channels.
- Localised volcanic seismic activity (e.g. earthquake swarms associated with magma movement, or larger earthquakes linked to eruption initiation) - mostly nearby effects.
Ruapehu is identified as the most prominent source of volcanic activity, particularly in relation to population centres such as Ohakune and Waimarino (National Park). A substantial eruption could result in significant impacts to critical infrastructure and economic sectors, notably tourism and agriculture. Furthermore, any eruption will likely have long-term impacts on the cultural and natural environments, including wāhi tapu (sacred sites) and wai māori (freshwater).
The Manawatū-Whanganui Region's boundary intersects these maunga, resulting in shared jurisdictional considerations with the Waikato Region. While Taranaki Maunga is not in the Manawatū-Whanganui Region, an eruption there could impact our region through ash dispersal and associated downstream impacts.
What you need to know
- Stay informed. Listen to the radio and follow official advice from Emergency Management and emergency services
- Stay at home unless you are told to evacuate. Do not go into the Tongariro National Park area. Avoid rivers and valleys as there may be lahars.
- Prepare your home for ashfall – see the next section below.
- Check on your neighbours and anyone who might need your help.
If ash fall is anticipated
- Before ash fall starts, get home if possible to avoid driving or walking during ash fall.
- Bring pets inside and move livestock into closed shelters. Make sure that animals have supplementary feed and access to clean drinking water.
- Close all windows and doors, shut down heat pumps and/or air conditioning units, and seal any ventilation intakes.
- Set up a single entry/exit point for your house. Place damp towels at the threshold to prevent ash being tracked indoors.
- Cover vehicles, machinery, spa pools and sensitive electronics indoors and outdoors. Do not remove covers until the indoor environment is completely free of ash. Ash can corrode metal surfaces and cause abrasion damage to windscreens and paintwork.
- Disconnect drainpipes/downspouts from gutters to stop drains clogging. If you use a rainwater collection system for your water supply, disconnect the tank.
- If you have a visual impairment, wear eyeglasses - not contact lenses. Contact lenses can trap ash which can scratch your eyes.
- Check on your neighbours and anyone who might need your help.
- Listen to the radio for updates. Follow official advice from Emergency Management and emergency services.
- Stay indoors. Volcanic ash is a health hazard, especially if you have respiratory difficulties such as asthma or bronchitis.
- Do not attempt to clear ash from your roof while ash is falling. Generally, you will be able to wait until ash fall has stopped before you need to clear ash from your roof. If there are cases where there is significant ash fall, carefully managed roof cleaning during ongoing ash fall may be undertaken if necessary and when advised by authorities.
- Keep pets indoors.
- Do not drive when there is ash on the road.
- Avoid unnecessary exposure to ash until it has settled.
- If you must go outside, use protective gear such as masks and goggles and keep as much of your skin covered as possible; wear eyeglasses, not contact lenses, as these can cause corneal abrasions.
- Continue to follow official advice from emergency management, emergency services and Department of Conservation. Stay out of restricted areas.
- If you have been evacuated, do not return home until told it is safe to do so by an official source such as emergency management or emergency services.
- Keep children indoors and discourage play in ash.
- Keep animals indoors until ash is cleaned up or washed away. If pets go outside, brush them off before letting them back inside.
- If your property is damaged, take photos for insurance purposes. If you rent, contact your landlord and contents insurance company as soon as possible.
- Check on your neighbours and anyone nearby who may need help.
It is important to clean up ash promptly, as it is a health hazard and can cause damage to buildings and machinery.
When cleaning up, follow advice and instructions from your local council and Emergency Management staff. Be aware that:
- ash clean-up is physically demanding and time-consuming
- in bulk, ash is much heavier than people often expect
- repeated cleaning may be necessary
- water restrictions are likely after ash fall.
When cleaning ash, make sure to:
- Use water very sparingly to avoid depleting water supplies.
- Wear protective clothing that covers your arms and legs, sturdy footwear, a properly fitted P2 or N95 mask, and goggles.
- If you have a visual impairment, wear eyeglasses. Do not wear contact lenses because trapped ash can cause corneal abrasions.
Cleaning up ash indoors
Clean up any ash indoors first to protect indoor air quality.
- Ash is much more abrasive than ordinary house dust. The best cleaning methods to prevent scratching damage are vacuuming and rinsing. Use water sparingly.
- If possible, clean electronic equipment with an air duster to avoid scratching delicate surfaces.
Cleaning up ash outdoors
Generally, you should wait until ash has stopped falling before starting any outdoor clean-up. Remove ash before rainfall if possible.
- When cleaning up ash, use shovels first, then brooms to reduce the amount of ash particles in the air. Do not wet and rub painted surfaces as ash is abrasive – use a brush instead.
- It can help to dampen ash when cleaning up but use water very sparingly. There will be water shortages, and wet ash can become a heavy glue-like material that can collapse roofs and other structures.
- Follow official instructions about ash collection and storage from your local council and Emergency Management Group.
- Do not dispose of ash into drains as it can cause blockages and be difficult to remove.
- More advice about cleaning up ash is available on the Get Ready website.
Lahar mapping in our region
Ruapehu is a composite andesitic stratovolcano. Throughout its historic and prehistoric records there have been frequent lahars (volcanic mudflows and debris flows) generated on its flanks, particularly where Te Wai ā-moe (the Crater Lake) overflows into the Whangaehu River and drains eastwards to the Desert Road Fault, where it then diverts southwards past Tangiwai.
