DENVER -- The city and county's Office of Emergency Management and Homeland Security made upgrades to its tornado warning system.
The changes were made after someone hacked into all 156 tornado sirens in Dallas, causing them to go off for nearly two hours.
Denver's OEM is making sure its sirens are not messed with.
"Every year we look at the system and say, 'how can we improve it?’” said OEM Executive Director Ryan Broughton.
Dallas and Denver use the same system called Federal Signal. The alarms are activated using audible signals. It’s similar to radio or TV broadcast, Broughton said. Once the signal hits the alarm, it then turns it on.
"The city of Dallas was hacked, and somebody recorded their live test signal and played it back," said Broughton.
The sirens in Denver can be activated from the OEM, Denver 911 or at DIA. The city holds 86 sirens. Each of them received new hardware, making it impossible for anyone to take over the system.
"We already had some of the procedures in place, but we found one thing missing," Broughton said. "We could encrypt the actual alert signal that tells the siren to activate."
The encrypt signal will make it harder for anyone to record it. Crews just finished with the upgrades on the sirens late Tuesday morning.
"Even if somebody tape recorded it, they could not play back and receive the same result," said Broughton. "They couldn't activate our sirens."
