Early warning system runs amok during storm surge: False sirens, wrong messages, and delayed evacuation orders
At 00:06 on the night between Friday and Saturday, the portable dam—water tube—at the Port of Aabenraa is breached.
“There is a breach in the set up dams, which means there is a risk of flooding, and you are in a dangerous area. Leave the area. Stay away from flooded areas. Only use 112 if necessary.”
Dramatic messages, while air sirens wail across most of Aabenraa and the surrounding area. TV Syd is at the Port of Aabenraa when the warning siren sounds, and it causes both the reporter and photographer to panic.
But sirens and mobile phone warnings are triggered in a too wide area, rather than only in the dangerous area at the Port of Aabenraa, and this creates a great deal of unnecessary worry and confusion among numerous citizens who are woken up by phone messages and air sirens far from the port.
Illustration: Aabenraa Kommune.
After the warning, people start calling the police service number 114. Many people in South Jutland do not understand why they have to abandon their homes and evacuate.
A short time later—at 00:32—a counter-order comes from the South Jutland Police. By mistake, the sirens have been activated in other parts of South Jutland, and not only for citizens who live very close to the Port of Aabenraa and the city centre.
“By mistake, the sirens have been activated in other parts of South Jutland. It is encouraged to pass this message on to other people in this area if possible.”
For some citizens, the concern only becomes even greater when they click on the link that the police have attached to the warning message, which is sent out via emails and mobile phone messages. The link does not work and leads to an error page.
“The police state that it was a human error that the sirens were activated in too large an area,” the Danish Emergency Management Agency writes in an email to Ingeniøren.
“It is correct that a wrong link was sent out with a warning via S!RENEN. This link has now been removed from the system,” the email continues.
The Danish Emergency Management Agency is responsible for the development and operation of the S!RENEN mobile-based public warning system.
- The current siren warning system was launched in 1989, and up to 1994, well over 1,000 sirens were set up, covering urban areas with over 1,000 inhabitants, corresponding to a potential coverage of approx. 80 percent of the population.
- However, the real coverage percentage is lower, as traffic noise and indoor sounds such as music and TV can drown out the sound of the siren.
- Since the turn of the millennium, no sirens have been installed, even though many new homes have been built. Since 2008, the authorities have had an SMS warning system for the deaf and hard of hearing, as well as a public warning app called Mobilvarsling. That app has been phased out.
- The new mobile-based public warning system does not replace the physical warning sirens.
In Denmark, it is the police who decide when a public warning should be sent out and define which geographical area is to be covered by the warning, just as they also formulate the actual message.
Illustration: Aabenraa Kommune.
The message then goes to the four Danish mobile operators, TDC NET, 3, Telia/Telenor, who then need to match the police’s defined geographical area to the available cell towers. The message is then sent out via cell broadcast technology. Cell towers can reach a range of up to 20 kilometres, and it can therefore be a challenge to limit a warning to a very narrow geographical area.
Alerts sent out hours after the wind died down
During Saturday morning, the wind dies down and the water recedes slowly. The sirens have been turned off, and an evacuation warning is sounded at the Port of Aabenraa.
But the challenges with the new mobile-based public warning system do not end here.
In the afternoon and evening, the phones start ringing again at the South Jutland Police. Many citizens are confused. They suddenly start receiving alerts on their mobile phones, even though it has been many hours since the warning was cancelled.
According to the South Jutland Police, the error has occurred because one or more cell towers in the area have been switched off due to a power failure.
As the cell towers have been switched back on during Saturday, they have sent out accumulated messages—including the alert from the night to Saturday.
Technically, this should not be possible, as cell towers only send alerts as long as the warning is active. If the power goes out before or in the middle of a warning, the individual cell tower will check whether the warning is still active when the power is back.
“We are clarifying the reasons why some alerts were sent out after the warning had been cancelled. Once the causes have been found, adjustments will be made so that similar cases are avoided in the future,” the Danish Emergency Management Agency writes to Ingeniøren.
S!RENEN mobile-based public warning system works as a traditional broadcast technology, which means that the data packets with warning messages are continuously sent out, so that citizens who move into the danger area also get the message. When the warning is cancelled, no new data packets should be sent out via cell towers, regardless of power failure.
The Danish Emergency Management Agency informs Ingeniøren that they will now evaluate the course of events in Aabenraa during the storm surge on the night to Saturday.
