Tsunami

All of New Zealand’s coastline is at risk of tsunami, including the Waimakariri District.

All of New Zealand’s coastline is at risk of tsunami, including our district - knowing the warning signs and the taking the right action promptly can help save lives.

In February 2021, new tsunami evacuation zones were released for Waimakariri after scientific modelling commissioned by Environment Canterbury, showed that flooding from a large tsunami could travel inland further than previously thought.

Remember: Long or Strong, Get Gone.  If you are near the coast (in a red or orange zone) and experience an earthquake that rolls for more than a minute OR makes it hard to stand up, don’t wait for an official warning. Move immediately inland until you are outside the tsunami evacuation zones. Stay there until you get the all clear from official Civil Defence sources.

View Evacuation Zone Maps

Tsunami Evacuation Zones

Waimakariri now has three tsunami evacuation zones: red, orange and yellow. There is no one tsunami that would flood the entire orange or yellow zones – rather it is an envelope around many possible 'worst case' tsunami scenarios.


Red evacuation zone

This is an area that is most likely to be affected by a tsunami. It includes estuaries, rivers, beaches and harbours. A tsunami of any size could cause strong currents and surges in the water. You can expect to evacuate the red zone several times in your lifetime.

You should leave this zone immediately, if:

  • You experience a long or strong earthquake
  • You see sudden sea level changes or hear unusual noises coming from the sea
  • You receive an official warning from Civil Defence Emergency Management

Orange evacuation zone

This area is less likely to be affected by a tsunami than the red zone. It includes areas on land that could be flooded in a large tsunami. You can expect to evacuate the orange zone a few times in your lifetime.

You should leave this zone immediately, if:

  • You experience a long or strong earthquake
  • You see sudden sea level changes or hear unusual noises coming from the sea
  • You receive an official warning from Civil Defence Emergency Management

Yellow evacuation zone

This is an area that is much less likely to be affected than the red or orange zones, but could be flooded or isolated in a very large tsunami. It is possible this zone will be evacuated sometime in your lifetime, however it is unlikely.

You do not need to leave this zone if you feel a long or strong earthquake.

You should leave this zone immediately, if:

  • You receive an official warning from Civil Defence Emergency Management.

Note: In most other parts of New Zealand, yellow zones need to be evacuated in a long or strong earthquake. You should check local tsunami evacuation zones when spending time on the coast.

No zone

This area is outside the tsunami evacuation zones. We do not expect to ever evacuate this area due to the risk of a tsunami.

If you’re in this area:

  • You don’t need to evacuate in a long or strong earthquake
  • You don’t need to evacuate if you hear the warning siren system
  • You don’t need to evacuate during an official tsunami warning from Civil Defence Emergency Management
  • You may wish to open your home to family or friends who need to evacuate from a tsunami evacuation zone

View a map of Waimakariri’s Tsunami Evacuation Zones

Tsunami Warnings

Natural Warnings

Some tsunami sources could arrive in minutes and there won’t be time for an official warning. It is important to recognise the natural warning signs and act quickly.

If you are near a shore (in a red or orange evacuation zone) and experience any of the following warnings, head immediately inland. Do not wait for an official warning and do not return until an official all-clear message is given by Civil Defence.

  • Feel a strong earthquake that makes it hard to stand or a long earthquake that lasts more than a minute
  • See a sudden rise or fall in sea level
  • Hear loud or unusual noises from the sea

Official Warnings

Official warnings will normally be issued by Civil Defence Emergency Management, Waimakariri District Council and/or emergency services.

They may arrive from a variety of sources including:

If there is an announcement to evacuate the zone you are in, follow the instructions immediately. Stay out of the evacuation zone until you are told by an official source that it’s safe to return.

Coastal Warning Sirens

There are three siren locations in the Waimakariri District, they are stationed in the coastal communities at The Pines/Kairaki, Woodend and Waikuku beaches.

The sirens are tested at least twice a year, usually on the first working day following the change to and from Daylight Savings.

If you hear the coastal warning sirens, comply with any of its voice messages and check the above sources for further information.

It is possible in some tsunami scenarios, that there won’t be sufficient time to activate the sirens.

When and How to Evacuate

Following a long or strong earthquake or an official evacuation warning - head immediately inland until you are outside of the tsunami evacuation zones.

If possible, make a plan now with family or friends who live outside the tsunami zone to stay with them if you need to evacuate.

In the case of evacuations, the Council will open Civil Defence Centres. Check the Waimakariri District Council website or Facebook page for their locations.

Stay Informed – keep checking official Civil Defence channels for up-to-date information. These include the Waimakariri District Council website and Facebook page, and radio stations such Compass 104.9 FM and Radio NZ.

Be prepared – Check out getready.govt.nz to make sure you’re prepared.

Have a plan – have an evacuation plan and escape route for your household, including pets. Think about where you would go and, if possible, make arrangements with family or friends who live outside the tsunami zone to stay with them if you need to evacuate. Share any official warnings you hear with family and friends near the coast.

Think about - what your family would do if it happened during working hours or when the kids are at school. Does you know your school or preschool’s plan?

Work or spend time in Christchurch? - Familiarise yourself with the tsunami evacuation zones on the Christchurch City Council website.

Potential Tsunami Sources

It’s impossible to predict the exact likelihood of a damaging tsunami.  Large tsunamis that flood land are rare, however they can (and do) happen sometimes.

The most likely tsunamis are those that won’t flood land, but can create strong currents in the ocean, river mouths and estuaries. They are expected to occur around once or twice a decade – maybe a handful of times in someone’s lifetime.


Distance Source Tsunami

A distant source tsunami is a tsunami that takes more than three hours to reach the coast from its source.

The most likely source for a tsunami, of any size, is expected from somewhere across the Pacific. All four significant historic tsunamis to affect Pegasus Bay have come from South America (1868, 1877, 1960 and 2010).

A distant source earthquake would not be felt along the Pegasus Bay coast, but there would be enough time to issue an official warning and, if the tsunami was coming from across the Pacific Ocean with a 12+ hour travel time, undertake a managed evacuation.


Regional Source Tsunami

A regional source tsunami is a tsunami that takes between one and three hours to reach the coast from its source.

A large earthquake on the Hikurangi or Kermadec subduction zone, off the north and east coasts of the North Island, could create a tsunami that could flood land and would reach Pegasus Bay in 1.5 to 3 hours.  The recurrence intervals of these faults are not well known but are probably in the order of several hundred years.

There would likely be time to issue an official warning before the first tsunami waves arrive, but the long earthquake should be people’s cue to evacuate because the official warning may not effectively reach everyone in time.


Local Source Tsunami

A local source tsunami is generated close to shore, usually by an underwater earthquake or

landslide, which takes less than one hour to reach the coast.

The likelihood of a damaging local source tsunami being generated off the Pegasus Bay coast is thought to be relatively low and the most likely effect if it did occur would be strong and unpredictable currents and surges in the water, and inundation of very low-lying land, depending on the tide stage.

There would not be time to issue an official warning before the first tsunami waves would be due to arrive.


Remember, if an earthquake is long or strong, get gone! Don’t wait for an official warning.

For more information about potential tsunami sources, please visit the ECan Website.

Frequently Asked Questions

Why do we need to update the tsunami evacuation zones?

The coastal townships of Woodend Beach, Waikuku Beach, The Pines Beach and Kairaki were already known to be potentially at risk and were included in the previous tsunami evacuation zones.

Scientific modelling completed recently shows that in event of a tsunami, flooding could travel further inland than previously thought. In rare, worst-case scenarios, parts of Kaiapoi, a small section of Pegasus and other residential areas near the coast, may be at risk of flooding.

As a result, we’ve introduced a yellow evacuation zone and updated the red and orange zones.  This three-colour approach is consistent with evacuation zones across the rest of Canterbury.

How accurate is the modelling?

This is the most accurate tsunami risk modelling completed for our coastline. It uses the best modelling available in the world and has been produced by GNS Science, one of New Zealand’s principal organizations for modelling tsunami risk. It has also been internationally peer reviewed.

You can find out more about the modelling on Ecan’s website.

Will this affect my properties LIM?

A Land Information Memorandum (LIM) is a document containing information that the Council holds about a property.

All known Natural Hazards information in the Waimakariri District is publicly accessible and included with a LIM. The new tsunami evacuation zones will be reflected in the LIMs of affected properties.

Will this affect my insurance?

If you're in a tsunami evacuation zones, we recommend you call your insurer to let them know. Please see this advice from the Insurance Council Of New Zealand.

What other work is being done?

We are currently working with local emergency services, Canterbury Civil Defence Emergency Management and other local Councils to prepare new tsunami response strategies for our affected communities.

The Council will be mailing all residents and property owners in the evacuation areas shortly and are planning a public education campaign around tsunamis which will include community meetings.

Canterbury Civil Defence Emergency Management are leading an initiative to update tsunami warning signage across Canterbury.

Will Kaiapoi and Pegasus get tsunami warning sirens?

The Council will review warning systems including sirens and signage as it prepares new tsunami response strategies. However it’s important to note, that the largest risk to Kaiapoi and Pegasus comes from a rare, distant-source tsunami in which we would have at least 12 hours’ notice.

Where can I read the underlying reports?

The review of Tsunami Evacuation Zones and underlying technical reports are available on Environment Canterbury’s website.

Community Tsunami Plans

Community tsunami plans

18 February 2021: Please note these plans are currently being updated. While they contain useful information, they feature maps with outdated tsunami evacuation zones. These documents will be replaced as we work with the affected communities to develop new plans.