It is important to know about the hazards that can affect our communities. The more we know about them the better we can plan for them causing an emergency.

Earthquakes

Earthquakes present the most significant hazard to South Canterbury as well as other parts of New Zealand. We do not experience them very frequently but they have the most capacity to cause widespread damage.

Of all the earthquake sources that can affect Canterbury, the Alpine Fault is the most studied. It is capable of generating a very large earthquake which will affect much of the South Island. It will produce the strongest earth shaking experienced in South Canterbury since European settlement.

Of course, there are other known fault lines in South Canterbury (and probably some we do not know about). Earthquakes are a very real hazard and their occurrence must be planned for.

Flooding

This is Canterbury's (and probably New Zealand's) most frequent emergency.

The Canterbury Plains were formed by alluvial gravels being deposited from the many rivers which cross them. Since European settlement, we have built communities on the plains and then tried to protect them from flooding by building stopbanks. Because the stopbanks are quite effective, more and more intensive land use of flood plains has occurred. That is okay until a flood exceeds the design of the stopbanks or they breach. Then people and property on the flood plain are in danger!

If you live, work, or your school is on a flood plain, you are at risk. You should inform yourself about that risk. Environment Canterbury has produced flood plain maps and staff there can tell you about the flood risk.

Many of the rivers in Canterbury build up to a flood over a period of time, ranging from hours to days. Some, however, flood with little or no warning. It is very important to understand the flood risk. You need to know what depth of water you could expect and how fast moving it could be (velocity). You also need to know the likelihood of getting flooded.

Declared Emergencies Caused by Flooding

Environment Canterbury can be contacted on: (03) 687 7800

You can check out river level and rain information on their website: www.ecan.govt.nz

Storms

The most likely meteorological event to cause wide scale emergency is a windstorm. These can be in two forms:

• A tornado can do great damage but is usually confined to a smaller area. These are pretty uncommon but have happened in the past.
• Cyclonic storms (usually from a southerly direction) and Fohn winds (north-westerly) can also cause damage and usually over a greater area.

Winds can damage buildings and overhead wires, uproot trees, blow vehicles off roads and cause debris to fly through the air. It is dangerous to go outside during a very high wind, so don't!

Canterbury can expect a damaging windstorm every 20 years on average. The last one happened in October 2000 and was mainly confined to Christchurch and Banks Peninsular. Prior to that, a severe windstorm affected all of Canterbury in 1974.

Because everywhere can be affected you should know what to do before, during, and after, a storm. Check out the Get Thru website - https://getready.govt.nz/

Tsunami

A tsunami is a series of long, powerful waves caused by a sudden disturbance in the sea or a lake. They are usually caused by large earthquakes displacing the sea floor, but can also be caused by underwater volcanoes or landslides under or into the water.

Tsunamis can cause strong and dangerous currents and surges in harbours, estuaries, river mouth and on beaches. Occasionally, tsunamis are big enough to rapidly flood land with debris-laden water, causing damage and injuries.

The whole Canterbury coast is at risk from tsunamis created both close to our shores and across the Pacific Ocean.

If you feel a long earthquake (more than a minute) OR a strong earthquake (where its hard to stand up) you should leave the blue tsunami evacuation zone as soon as the shaking stops.

Do not wait for an official warning, siren, emergency mobile alert on your phone, or for someone else to tell you to go – there may not be time to issue an official warning.  Stay away until you are told it is safe to return – the first tsunami wave may not be the largest and waves can continue for many hours or days.

If a tsunami is coming from further away, from the Pacific Islands or across the Pacific Ocean, you won’t feel the earthquake but there will be time to issue an official warning. This will tell you which areas to evacuate or stay out of.  You may not need to evacuate the whole zone, you may just need to stay out of the sea, lagoons, estuaries, river mouths and off beaches.

For more information on tsunamis and what you should do, you can visit the Canterbury CDEM Group or the Environment Canterbury tsunami pages.

What should I do if I have to evacuate?

To be prepared to evacuate, either on a natural warning (a long OR strong earthquake) or in an official tsunami warning, think about:

• Where you will go.  It is best to go to friends or family outside the blue tsunami evacuation zone in the first instance.
• Practicing your evacuation route.  Work out the best route for you and your household to get out of the tsunami evacuation zone, and practice it so you are all familiar with it before you need it.  Civil Defence won’t be able to personally help you evacuate so you need to think about this in advance. Check on your neighbours to see if they will need help evacuating.
• What you need to take. You may be away from your house for many hours in a tsunami evacuation. Take essential items that you can easily find and carry such as water, snacks, warm clothes, medication, supplies for babies and pets, and copies of important documents.
• Your animals. Take your pets with you if you can, they are your responsibility. Civil Defence Centres generally will not accept pets, apart from service animals. If you are farming along the coast, evacuate your family and staff first. Move livestock to higher ground only if you have time in an official tsunami warning.
• Where to find information during a tsunami evacuation. The best places to find information are:
  • cdemcanterbury.govt.nz
  • timaru.govt.nz
  • Radio New Zealand
  • Newstalk ZB

If you are not in the blue tsunami evacuation zone you do not need to evacuate after a long or strong earthquake or in an official tsunami warning. You can evacuate if you want to, but please be mindful of keeping roads clear for others who do need to evacuate.

• Canterbury tsunami brochure 2026 (pdf, 1.9 MB updated 06-Oct-2026)

Our bulletin boards around the coastline will be updated during October to show the new single Blue Zone.  These help people understand what areas could be affected and what areas they can go to for safety.

Manmade/Technological

Do you remember all the fuss about the "Y2K Bug"? That was an example of a potential manmade hazard. We could plan so well for it because we knew when it may occur.

Timaru has had two declared emergencies for manmade events:

• 1975 when gas from the gas works leaked into the sewer.
• 1994 when a building containing grain threatened to explode because the grain got wet.

Many transport routes (roads, rail, ports and airports) convey hazardous materials. If something goes wrong (e.g. a chemical spill), it may require evacuation of many houses.

Other examples of manmade hazards are:

• Transport accidents involving many passengers (e.g. cruise liner, train)
• Transport and industrial accidents involving leaking chemicals or gas
• Widespread and prolonged disruption to services (e.g. power, sewer, water)
• Space junk falling to earth

Last updated: 06 Oct 2026