The City and County of Denver’s Outdoor Warning Siren System was installed between 2012 and 2014. There are 86 sirens citywide: 75 in the city and 11 at Denver International Airport (DEN). Up until 2023, the sirens were primarily used for tornado warnings, however, following recent local and national disasters, the city updated it's policy to allow the city to activate their sirens for any imminent or widespread emergency including, but not limited to events such as tornadoes, dam failure resulting in dangerous flooding, wildfires, and hazmat situations.
When sirens are sounded, people are encouraged to take shelter immediately and tune into their phones, computers, and local media for subsequent alert and warnings and further instructions on how to remain safe and protected. Sirens do not send an “all clear” message. If sirens continue to sound, people need to continue to be follow prescribed recommended action(s) to remain safe.
When you hear a siren in Denver, you're encouraged to:
- Seek shelter indoors, immediately and close your homes windows and doors.
- Once you are inside a secure location, tune to local media (TV, radio, social media, mobile device) or NOAA weather alert radio to inform yourself of the emergency and hear what you need to do to remain safe.
- Follow all guidance and recommendations issued to, they could save your life.
In addition to our alerting technology, we encourage members of the public to follow our social media at facebook.com/DenverOEM and X.com/DenverOEM (formerly Twitter) to receive important information, including life-safety guidance during emergencies and disasters.