Christchurch’s 45 tsunami sirens will be removed from next week after the city council opted to use Emergency Mobile Alerts as the primary warning method.

From Tuesday, the current three tsunami evacuation zones — red, orange and yellow — will also be replaced to a single blue tsunami evacuation zone.

The change follows updated national guidance from the National Emergency Management Agency, which requires all councils across New Zealand to move to the national single blue zone by 2031.

The zone change also marks the start of work to remove Christchurch’s tsunami warning sirens, following a city council decision made in June last year.

Photo: CCC

City council head of civil defence and emergency management Brenden Winder said in a statement the move to a single evacuation zone will make it easier for people to know when to act during a tsunami evacuation.

“The new blue tsunami evacuation zone provides a simpler and more consistent approach that will help people make quicker decisions. If you’re in the blue tsunami evacuation zone and you feel a long or strong earthquake evacuate immediately. Don’t wait for an official warning, you should move immediately inland or to higher ground.”

Winder said updated tsunami modelling means some zone boundaries have changed, so it is important for residents to check whether their property is within the new blue zone when it takes effect.

“We’ll be updating our online map to show the new blue zone when it comes into effect in October. When the change happens, I encourage everyone currently living in a tsunami evacuation zone to check if their property is still within it.”

 

There are three tsunami evacuation zones for Christchurch and Banks Peninsula, which can be found at ccc.govt.nz/services/civil-defence/tsunami-evacuation-zones-and-routes

The siren removal decision followed a review of the city council’s tsunami alerting system, which found sirens can create confusion about what action people should take during a tsunami evacuation and are not aligned with national and international best practice.

The review recommended natural warning signs, such as a long or strong earthquake, and Emergency Mobile Alerts be used as the primary warning methods.

“We understand tsunami sirens have been part of Christchurch’s warning system for many years, and their removal may cause uncertainty for some people,” said Winder.

“Our priority is keeping people safe. Moving to natural warning signs and Emergency Mobile Alerts supports a simpler, more effective warning system that helps people know when to act and what to do.”

To coincide with the new blue-zone rollout and removal of the siren network, Christchurch and Banks Peninsula will receive dedicated tsunami information signage for the first time.

The signs will be installed at key public locations within the blue tsunami evacuation zone and will help people identify that they are in a tsunami evacuation zone and what actions to take in an emergency.

“Whether you’re a resident, visitor or just passing through, we want everyone to have the information they need to act quickly and keep themselves safe during a tsunami evacuation,” he said.