Northland's tsunami siren testing was called off at the last minute over the weekend after a warning by New Zealand's civil defence chief.
Northland Civil Defence Emergency Management (CDEM) Group had been planning to go ahead with its usual end-of-daylight-saving testing of 200 sirens – New Zealand's largest network of its type - around the region on Sunday, in spite of the Covid-19 lockdown.
But a formal directive from Civil Defence director Sarah Stuart-Black on Saturday afternoon - less than 24 hours before the testing was due to start - ordered tsunami siren testing not proceed.
"I am of the opinion that testing a tsunami warning system may substantially contribute to the Covid-19 emergency by confusing the Government's alert level 4 instructions, causing people to move beyond their self-isolation 'bubbles', and potentially causing people to congregate in open places eg on evacuation routes," Stuart-Black said in her directive.
"In doing so, testing a tsunami warning system may also lead to individuals breaching the orders issued by the Director-General of Health under sections 70(f) and 70(m) of the Health Act on 3 April 2020 and 25 March 2020 (respectively).
"A person commits an offence who intentionally fails to comply with a direction given under section 91 of the CDEM Act 2002."
By Saturday afternoon, at the time of the directive, Northland CDEM Group had already widely promoted the testing. More than 150 volunteers were on standby to monitor the sirens for faults.
Stuart-Black said the 2pm directive came after a national-level request had already been made.
"The National Emergency Management Agency had previously requested to CDEM Groups through its usual channels that tests not proceed at this time, and the directive was later issued to ensure that this request was adhered to."
Northlanders were notified of the cancellation via the Northland Civil Defence Facebook page about 2.45pm along with notifications to mobile phones via the Red Cross Hazard app shortly after.
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Northland CDEM executive group chairman Tony Phipps did not wish to comment on why the group had proceeded with its tsunami siren testing plan when civil defence groups had, prior to the directive, been told not to do so – other than to say it had cancelled it due to that directive.
Northland CDEM group manager Graeme MacDonald said late last week that the test was still taking place because New Zealand's tsunami risk was no different from its usual level.
"We're very much aware Northlanders have come through an extended period of drought and straight into the current nationwide lockdown," MacDonald said at the time.
"We also know we have people in the region at the moment who don't normally live here.
"So even though we know people are unsettled, we would not be doing them any favours if we didn't continue to test and maintain this valuable regional warning system."
Sirens from Te Hapua near Cape Reinga to Mangawhai in the south as well as Ruawai in the west would have been checked on Sunday as part of ongoing work ensuring the critical life-saving performance of New Zealand's biggest tsunami siren network.
More than 200 outdoor tsunami sirens around Northland – along with several hundred synchronised indoor sirens - were to sound simultaneously during the testing, firstly at 10am for 10 minutes and then at 10.30am for 30 seconds.
MacDonald said last week the volunteers had been briefed on how to do their monitoring safely under the level 4 lockdown.
Northland's tsunami sirens are funded and owned by the region's three district councils (Far North, Whangārei and Kaipara) and operated in a partnership which also includes the region's two electricity networks - Northpower and Top Energy.
Tsunami are one of Northland's main officially recognised natural disaster risks. They are in the top half dozen hazards the region faces, those generated from distant sources across the ocean ranked just ahead of locally-generated tsunami - such as happened with the 2016 Kaikoura earthquake.