Why doesn’t Wellington have tsunami sirens?


The only warning Wellingtonians will get before a tsunami is a long or strong earthquake, with national emergency teams agreeing sirens could cause more harm than good.

The risk comes from the potential for sirens to fail – if people wait for a siren that never comes, they could delay getting to safety.

Wellington Region Emergency Management Office (WREMO) regional manager Jeremy Holmes said tsunami sirens were ‘unsuitable as a warning system in areas subject to locally sourced tsunami, such as Wellington’ .

This position was international best practice, Holmes said, and the National Emergency Management Agency (NEMA), GNS Science and the New Zealand Tsunami Task Force agreed.

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Damage from an earthquake itself could cause sirens to fail, Holmes said. Time was running out because a tsunami could arrive in as little as 10 minutes.

“The time it takes for scientists to determine if an earthquake has created a tsunami threat and then issue official warnings may be longer than the time it takes for a locally sourced tsunami to reach the coast. .”

A tsunami evacuation line in Lyall Bay, Wellington.

Rosa Woods / Stuff

A tsunami evacuation line in Lyall Bay, Wellington.

Wellington’s wind made the sirens less effective, a problem they heard about every time the sirens were tested across the country. “If you expected to hear a siren and you didn’t, you can’t evacuate,” Holmes said.

People in tsunami zones should go to higher ground or inland more if they feel an earthquake lasting longer than a minute or strong enough to knock you down, he said.

Lower Hutt had sirens installed in the 1970s for flood warnings, not tsunamis. These sirens tell people that there might be danger, and that they should listen to the radio and seek further information online.

These were used in Lower Hutt after the 2016 Kaikoura earthquake and caused widespread confusion. WREMO’s position was that they would no longer be used in this way.

In Mount Maunganui and Pāpāmoa, funding for a mermaid system was withdrawn in May, one of the reasons being international evidence showing the risks associated with community reliance on a mermaid.

Napier’s was pulled in February for the same reason, and after a two-year fight in the Coromandel, a community group announced they would buy theirs after the council pulled the plug.

Timaru has a civil defense siren system, like this one on North Street.


Timaru has a civil defense siren system, like this one on North Street.

Northland, Christchurch and Timaru have active siren systems, as well as parts of Auckland.

NEMA communications manager Anthony Frith said regional civil defense groups have a great deal of autonomy in how they choose to alert their communities.

In areas where residents lived close together and didn’t have reliable phone reception, they might decide that a siren was the best option. Other regions might decide it’s not an effective tool and turn to methods such as phone alerts, he said.

For areas science indicates will be more prone to tsunamis with little warning, a siren would be less effective and people would have to evacuate to higher ground if they felt a long or strong earthquake, said Frith. “Long or strong, go.”

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