Tsunami evacuation zones

If a tsunami warning is in effect, it will be posted on the National Emergency Management Agency website: civildefence.govt.nz and in the yellow box on the top right hand side of our website homepage.

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Updated Tsunami Evacuation Maps

Thanks to support from the Natural Hazards Commission Toka Tū Ake (NHC) , Northland’s tsunami evacuation maps have been updated with more accurate modelling and information. These new maps better reflect how tsunamis are expected to behave as they travel across the ocean and reach our coastline.

Simplified Evacuation Zones

To make evacuation zones easier to understand, we have simplified the system from a three-colour scheme to a single colour system – the BLUE ZONE.

BLUE ZONE: Tsunami Evacuation Zone

  • This evacuation zone shows the areas that should be evacuated in the event of a tsunami warning. It represents where the water could reach in a tsunami.

SAFE AREA

  • If driving, keep going once out of the evacuation zone to allow room for others.

Modelling behind the zone

The Blue Evacuation Zone was created using new and improved modelling techniques. This new modelling aggregates the strongest tsunami threats from multiple sources. Previous models were simpler and, as a result, overstated the expected inundation extents. The updated inundation areas were developed using a hydrodynamic model that has been shown to be accurate against measurements of recent historical events in New Zealand and other locations overseas. This model accurately covers Northland's coastline, including the open coasts and the shorelines of numerous harbours and estuaries. The tsunami wave propagation was dynamically modelled across all these regions.

However, it is important to note that some areas may not be perfectly represented due to any potential errors in the underlying topographic model. Therefore, we still advise everyone to err on the side of caution and evacuate coastal and flood-susceptible areas when a warning has been issued. This is why even elevated areas near the coast may be included in the zone. These areas could also face other hazards from tsunamis, such as coastal erosion. In the event of a warning, we want people to evacuate the Blue Zone and any other areas susceptible to coastal flooding until we can confirm the risk has passed. 

To find out more about how this zone was created and the modelling behind it, you can view the full report here: https://www.nrc.govt.nz/environment/natural-hazards-portal/tsunami/tsunami-modelling/

We encourage you to:

Natural warning signs

For a local source tsunami which could arrive in minutes, there won't be time for an official warning, so you need to be able to recognise the natural warning signs and act quickly if required.

If you are at the coast and experience any of the following:

  • You feel a strong earthquake that makes it hard to stand up, or a weak rolling earthquake that lasts more than a minute, or
  • You see a sudden rise or fall in sea level, or
  • You hear loud and unusual noises from the sea, especially roaring like a jet engine.

Move immediately to higher ground or as far inland as you can, without waiting for an official warning.

Official warnings

Civil Defence warnings to evacuate your area - when possible - will come via:

Immediate evacuation

In the event that an immediate evacuation of tsunami zones is directed:

  • Move immediately to the nearest high ground, or as far inland as you can
  • Walk or bike where possible and drive only if essential. If driving, keep going once you are outside of evacuation zones to allow room for others
  • Remain there until an official all-clear message from Civil Defence
  • Stay up-to-date via radio, TV or social media - Civil Defence Northland Facebook
  • Share warning information with family, neighbours and friends in tsunami evacuation zones
  • Stay off beaches and shore areas and out of the water (sea, rivers and estuaries – this includes boats)
  • Do not go sightseeing.

The first wave may not be the most significant – there may be multiple waves which continue for a number of hours.

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