Denver’s Outdoor Warning Sirens: What To Do When They Sound:
The City and County of Denver has an outdoor warning siren system consisting of 76 electro-mechanical sirens (including nine at Denver International Airport). The sirens are tested on the second Wednesday of each month at 11:00 a.m.
Aside from the monthly tests, the siren system is only activated when a tornado has been spotted by trained observers, or when the National Weather Service has issued a Tornado Warning for Denver County
. A Tornado Warning means that a tornado has been sighted, or that a developing tornado is reported by trained spotters or indicated on Doppler radar. A warning is typically issued for a small area for less than an hour. Denver
’s siren system can be activated for either the entire county or for specific affected areas.
Questions and Answers about the Denver Outdoor Warning Sirens