Denver tornado sirens set off by mistake — here’s what went wrong

If you were in Denver on Monday afternoon and thought you heard tornado sirens wailing, you weren’t imagining it — but you also weren’t in danger. Just after 4 p.m., as a tornado watch was already in effect across much of the Front Range and eastern Colorado, the city’s outdoor warning sirens blared for a full three minutes. The problem? There was no tornado warning issued for Denver at the time. A 911 caller had reported a tornado on the ground, and a Denver Fire Department employee — without going through the proper verification steps — walked up to a physical black box and manually pressed the button to trigger the sirens. The system itself worked exactly as designed. It just shouldn’t have been turned on.

Following a review, the City and County of Denver’s Office of Emergency Management confirmed it was not a technology failure, but rather “human error and an improper understanding of protocol.” The standard procedure requires the National Weather Service to issue an actual tornado warning — not just a watch — before sirens can be activated, and any manual activation should also be accompanied by a cell phone alert to residents. Neither of those steps were followed. OEM spokesperson Loaitza Esquilín García said the city is now implementing corrective actions, including a comprehensive review of alerting policies and enhanced training for personnel involved in emergency alerting operations.

And here’s the kicker — this wasn’t a one-time oops. Monday’s false alarm was actually the third time in just five months that Denver accidentally pushed out a citywide emergency alert. Back in January, residents received a warning about an “active threat” near the University of Denver that was broader than intended, and in April, a robbery alert in the Ruby Hill neighborhood was mistakenly sent to the entire city. At this point, Denver might want to double-check that protocol a little more carefully before hitting any buttons.