Dallas Reveals Radio Signals, Not Network Hack, Triggered Emergency Sirens

Just before midnight on April 7, the city of Dallas experienced a rather rude awakening as all 156 of its emergency sirens were hacked, causing a ruckus that lasted 90 minutes.

Although Dallas’ Office of Emergency Management won’t reveal much about the hack for security reasons, they recently revealed the work to be not a hack of network systems, but through a radio or telephone signal.

"It's a radio system, not a computer issue," Dallas City Manager T.C. Broadnax said Monday morning, Dallas News reports. "As we brought the system back up, some encryption was added as part of our process to prevent this type of error from occurring going forward."

The city's outdoor warning system was installed over a decade ago and city officials were unaware that the signals could be compromised in this manner.

"No one had ever seen anything like this," said Sana Syed, the city's spokeswoman, Dallas News reports. "No one had ever seen anyone able to break into the entire system and impact every signal."

Ever wonder what the end of the world feels like? #dallas #sirens pic.twitter.com/dvokKWkZ6N

— ManicPixieDreamGay (@deadlyblonde) April 8, 2017

The city’s OEM immediately began procedures to deactivate “the entire outdoor warning system,” according to a statement on the incident, but the malfunction also served to overwhelm 911 call centers. According to the OEM, the call center received more than 4,000 calls from 11:30 p.m. to 3 a.m. on April 8, as a result of the sirens — a rather sharp increase from the average of 80 calls the center usually receives during this time.

Outdoor warning siren system has been manually shut down. Looking into the cause for the unintended activation. Our Sincere apologies.

— DallasOEM (@DallasOEM) April 8, 2017

The emergency alert system is now back up and running, and the city has enlisted the Federal Communications Commission to look into the incident.