Tsunami

Selwyn Tsunami Evacuation Zones

The Red Zone – This zone covers marine and beach areas and Te Waihora Lake Ellesmere. In a small tsunami Civil Defence may warn people to stay away from beach and marine areas and off the lake due to strong and unpredictable currents and waves.

The Orange Zone – Covers the coastal area of Selwyn and around the edge of Te Waihora Lake Ellesmere. The boundaries for this zone are based on scientific advice of the maximum credible event that could impact Selwyn. They are regularly reviewed to take into account the latest research. If Civil Defence issues a warning to evacuate the Orange Zone, all people in this zone should immediately implement their emergency plan and evacuate – preferably to a relative or friend’s address outside the Orange Zone, or otherwise to one of the three Emergency Centres listed below.

Evacuation Centres

Southbridge Hall – this centre will be staffed by volunteers from Southbridge. It will provide information and basic refreshments to evacuees.

Leeston Library Community Room – this facility will be staffed by volunteers from Leeston. It will provide information and basic refreshments to evacuees.

Lincoln Event Centre - this centre will be staffed by volunteers from Lincoln and Selwyn District Council staff. LEC is a designated welfare centre for Selwyn District and has emergency power and the capacity to provide emergency shelter to evacuees for a period of days if necessary. If evacuees are required to stay overnight they will be transported from Southbridge and Leeston to LEC.

How Warnings Are Communicated

In Selwyn district we make use of the Selwyn Gets Ready system. The systems allows Civil Defence personnel to send emergency and evacuation warnings via text message and email. You can sign up for your home.

Warnings will also be sent via the Emergency Mobile Alert (EMA) system that is managed by Canterbury CDEM Group.

Volunteer Community Response teams will also door-knock in affected townships if there is time.

In an Orange Zone evacuation council and emergency service personnel will also attempt to warn residents using emergency vehicle sirens in affected communities.

However in a close to shore Tsunami there will not be time to issue an official warning. If you are at the coast and experience any of the following:

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

Move immediately to the nearest high ground, or as far inland as you can.

General Tsunami Advice

New Zealand’s entire coast is at risk of tsunami. A tsunami can violently flood coastlines, causing devastating property damage, injuries and loss of life.

A tsunami is a natural phenomenon consisting of a series of waves generated when a large volume of water in the sea, or in a lake, is rapidly displaced. A tsunami can be caused by large submarine or coastal earthquakes; underwater landslides which may be triggered by an earthquake or volcanic activity; large coastal cliff or lakeside landslides; or volcanic eruptions beneath or near the sea.

There are three distinct types of tsunami. The type you encounter depends on the distance you are from the place where it is generated.

Distant tsunami are generated from a long way away, such as from across the Pacific in Chile. In this case, we will have more than three hours warning time for New Zealand.

Regional tsunami are generated between one and three hours travel time away from their destination. An eruption from an underwater volcano in the Kermadec Trench to the north of New Zealand, could generate a regional tsunami.

Local tsunami are generated very close to New Zealand. This type of tsunami is very dangerous because there is no time to issue and official warning and you may only have a few minutes to act.

Have a look at this video from Taranaki Civil Defence and GNS Science which shows the difference between normal wave action and a tsunami:

Surviving a Tsunami

Before a Tsunami

Getting ready before a Tsunami strikes will help reduce damage to your home and business and help you survive:

• If you have a disability or special requirements, arrange with your support network to alert you of any warnings and emergency broadcasts. You will need to have your own evacuation plan in place as emergency services will be stretched.
• Develop a Household Emergency Plan
• Have a Getaway Kit ready
• Know where you will evacuate to (this could be a relative or friends house outside the Orange Zone or an Emergency Centre at Lincoln, Leeston or Southbridge). Plan your escape route for when you are at home, as well as for when you may be working or holidaying near the coast.

During a Tsunami

• Take your Getaway Kit with you if possible. Do not travel into the areas at risk to get your kit or belongings
• Take your pets with you if you can do so safely
• Move immediately to your safe area (this could be a relative or friends house outside the Orange Zone or an Emergency Centre at Lincoln, Leeston or Southbridge)
• If you cannot escape the Tsunami, go to an upper storey of a sturdy building or climb onto a roof or up a tree
• Boats are usually safer in water deeper than 20 metres than if they are on shore. Move boats out to sea only if there is time and it is safe to do so
• Never go to the shore to watch for a tsunami. Stay away from at-risk areas until the official all-clear is given. This message will be sent by text and email on Selwyn Gets Ready. Make sure you are signed up so you receive these messages
• Listen to the radio or television for Civil Defence advice.

After a Tsunami

• Continue to listen to the radio or television for Civil Defence advice and do not return to the evacuation zones until authorities have given the all-clear
• Be aware that there will likely be more than one wave and it may not be safe for up to 24 hours, or longer. The first wave is not necessarily the biggest.
• Check yourself for injuries and get first aid if needed. Help others if you can
• Do not go sightseeing
• When re-entering homes or buildings, use extreme caution as floodwaters may have damaged buildings. Look for and report broken utility lines to appropriate authorities
• If your property is damaged, take notes and photographs for insurance purposes. If you rent your property, contact your landlord.

If you would like further information please contact the council’s emergency management team on 03 347 2800.

Find Canterbury tsunami hazard reports here.