Emergency mobile alerts - how they work, why you're getting them

RNZ News

24-05-2025

Photo:
RNZ
Explainer:
Brace yourself - your phone will make itself heard on Sunday night.
The annual
national test
of the emergency mobile alert system is scheduled for between 6-7pm.
That distinctive buzzing alarm may come as a mild shock to the system, but it can be a matter of life and death, says the National Emergency Management Agency Te Rākau Whakamarumaru.
"If you get an alert, you should stop and read the message, and take it seriously," NEMA civil defence emergency management director John Price said. "It will tell you what the emergency is, what to do and where to go for more information."
A warning broadcast to your mobile phone, they've been around in New Zealand since 2017. They come with a loud buzz that can usually be heard even if you're on silent mode and a banner notification detailing the emergency.
When you hear this, it's time to pay attention.
They've been used for everything from tsunami warnings to dangerous fires to thunderstorms.
Many other countries use them
and they got a particularly good workout in New Zealand
during the Covid-19 pandemic
.
More recently, in April, Auckland saw several emergency alerts during stormy weather
over Easter weekend
and a
recycling plant fire
that sent dangerous smoke soaring over the motu.
About 200 alerts have been sent out since they began, many of them regional ones, NEMA communications manager Anthony Frith said.
NEMA expects "about 5.5 million phones to go beep on Sunday".
The annual test is an important way to make sure the system is working properly all across the country, Firth said.
"We're always wanting to have that assurance that the system is working as it should. We need to have assurance that it's going to work for the whole country, if it's needed.
"There will be a lot of people in Auckland who say, 'Oh, I just received an alert the other week', but there will be people who haven't received one since the last test."
The test will go out to millions of phones on Sunday.
Photo:
RNZ/ Karoline Tuckey
Alerts use cell broadcast technology known as geotargeting to send alerts through cell towers in a selected area - which can be the entire country, as in Sunday's test, or down to a small section of a city.
New Zealand's system was provided by
Dutch company one2many
, which is now a division of
Everbridge Public Warning
, an American software company that specialises in alert systems.
In a
description of their technology
, Everbridge says "one message can be sent to millions of devices within a target area in seconds".
"A really oversimplified way of putting it, it's like a signal that your phone picks up, which is almost like radio," Frith said.
When an alert is issued, the agency involved will select how big a region is covered, depending on the specific crisis.
"The operator who sends the emergency alert will draw a polygon around that area, a shape they need to make sure is big enough to capture cell phone towers in the perimeter," Frith said.
Auckland Emergency Management general manager Adam Maggs said, while targeted messages work well, who gets them varies, depending on a variety of factors.
"In terms of one person [in a household] receiving a message and another not, this could be due to being just outside of the geographically targeted area. The boundary for the geotargeted area is not a 'hard' boundary and there can be message leakage, depending on the location of cell towers.
"Other reasons include having a phone that may be older or has missed a software update, or the phone may not have had mobile reception."
They don't. The system uses the cellphone network as a carrier of the notifications that NEMA or other emergency agencies send out.
"Our system does not have any telephone numbers," Frith confirmed. "Once we've transmitted the message from our portal, it then goes to the cell towers."
Heavy storms hit Auckland during Easter weekend, triggering some alerts.
Photo:
RNZ / Calvin Samuel
Only certain agencies have the power to send out alerts - NEMA, Civil Defence Emergency Management groups, NZ Police, Fire and Emergency New Zealand, the Ministry of Health and the Ministry for Primary Industries.
Maggs said there was a protocol in place around how the messages were sent.
"For civil defence groups (like Auckland Emergency Management), the controller or group manager will make the final call to issue an alert for a hazard or warning that relates to their work.
"Similarly, Fire and Emergency or NZ Police could issue an alert about a response that they are leading. We all use the same protocols to assess whether an EMA might be used, with criteria based on certainty, severity and urgency."
The timing of
emergency alerts during Auckland's Good Friday weekend storms
was questioned.
NEMA's Frith noted the fast-moving late night Friday thunderstorms were not preceded by a MetService warning. The next day, Saturday, saturated soil and people travelling
triggered alerts that day
.
"We've got really clear protocol for use of the system," he said. "It's really important we don't overuse it, so we can only use it when an event is fairly certain and likely to be pretty severe.
"We're not going to be able to issue an alert before every event happens."
What appears to have been the first emergency alert sent out in New Zealand was a localised one about
a New Plymouth ammonia leak in February 2018
.
Then, during the Covid-19 pandemic that began in 2020, the agitated buzz of lockdown or new case announcements on our phones became commonplace. Covid was the first time alerts were used on a national level, Frith said.
While we often see weather-related alerts, the alert system has a variety of applications.
For instance, on 9 April, Greymouth sent out an emergency alert for a
boil water notice, after possible contamination
.
Grey District Council communication and engagement manager Laura Mills said that call was made by the council's executive leadership team and emergency management staff, in consultation with NEMA.
"It had to be determined if the boil water alert met the criteria," she said. "It did and a map was supplied, so phones in the affected area could be 'pinged'.
"It definitely got the message out quickly and it helped ensure people took the message seriously."
Boiling water may not seem to be the same as a tsunami alert, but it's an important health issue, Frith said, citing a
2016 camplyobacter outbreak in Havelock North
that sickened thousands and left four people dead.
"If you cast your mind back to what happened in Havelock North in 2016, over 5000 people got sick... so a boil water notice can actually be quite important."
The first national emergency alerts were sent during the Covid-19 pandemic during Prime Minister Jacinda Ardern's leadership.
Photo:
POOL / Stuff / Robert Kitchin
The alert system generally reaches nine out of 10 phones, Frith said, but while it's an important tool, it's not meant to be the only way people learn about emergencies.
"We want to stress that this is really valuable, but often nature is the first warning.
"Other channels are really important. The media is the No.1 information channel in emergencies."
The alert doesn't replace radio, the internet or the need to act when you see natural warning signs.
"If you feel like your life is in danger, don't wait for an official warning or alert - take action and get yourself and your whānau to safety," NEMA's Price warned.
"If floodwaters are rising, self-evacuate and move to higher ground. If you are near the coast and an earthquake is long or strong, get gone.
"Move immediately to the nearest high ground or as far inland as you can."
NEMA also said the annual alert test is a good time to examine emergency plans. The
Get Ready website
is full of information about how to do this.
Frith acknowledged "we'll never get to 100 percent" coverage with the alerts.
"There will always be a percentage of the population that don't have phones or don't have smartphones. There's no mass communication channel that will reach absolutely everyone."
No.
You can't choose not to receive an emergency alert - after all, the point is that it's meant to be used for an emergency. Because it's sent out over cell phone towers, there's no 'list' of names on it to be removed from.
If you don't want to be disturbed by Sunday evening's test, you could turn off your phone entirely or switch to airplane mode.
The flurry of alerts sent out in Auckland in April saw some backlash on social media.
"We often receive feedback from Aucklanders asking to be removed from the EMA system [which is not possible]," Maggs said.
"We get just as much feedback thanking us for an alert or update. This will always be the case and we are fine with that.
"At the end of the day, our goal is to help Aucklanders stay as safe as possible in times of emergency and we will continue to work hard to ensure that."
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