DENVER — "Human error" and "an improper understanding of protocol" caused an unwarranted tornado siren to erupt around Denver on Monday amid severe storms, though no tornado warning was ever in place for the city, Denver's Office of Emergency Management said in a statement Tuesday morning.
The siren was "inadvertently set off" while Denver County, as well as several other neighboring counties, were under a tornado watch and severe thunderstorm warning, the city said Monday. At the time, a spokesperson said they were checking to see if the error was due to a technology malfunction or a human error.
On Tuesday morning, the city confirmed it was the latter.
"Following a comprehensive review, the City and County of Denver determined that Monday’s inadvertent activation of the outdoor warning sirens was not caused by a technology failure or malfunction of the siren system but rather human error and an improper understanding of protocol," the city told Denver7. "While the siren system functioned as designed, the activation itself was not warranted, as there was no tornado warning in effect for Denver at the time."
The city called this a "serious matter" and it is "implementing corrective actions." That will include a review of alerting policies, as well as "enhancements" to training and exercises for the people responsible for these alerts.
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"We have a responsibility to provide residents with timely, accurate, and reliable emergency information, and we are committed to continuously improving our processes to ensure that responsibility is met," the city's statement reads.
Denver has 86 sirens, which are mapped out on the city's website here.
Denver7 spoke with multiple residents who heard the siren Monday and expressed concern about real alarms versus false ones.
"I just hope it's not a repeated thing, because of the whole boy who cried wolf thing. Would people continue to take it seriously if this were to keep happening?" said Jamie Preston, who lives around Capitol Hill.
▶️ WATCH: Hear more from the community about Monday's tornado siren in our report below.
Denver sent out two other mistaken alerts earlier this year.
In January, a barricaded person near the University of Denver prompted a city-wide shelter-in-place alert, leaving thousands confused about why they received the alert. Andrew Dameron, director of Denver’s 911 Communications Center, said the shelter-in-place alert was intended for a two-block radius around the home and that supervisors working that night “followed all of the appropriate policy and procedure” to make sure the alert would only go to those homes.
However, a "configuration issue on the back-end of the vendor software" got in the way of that, he said. Instead of using a map of the specific impacted area for the alerts, the software sent it to the entire county.
Then, in April, an emergency alert meant for a small area was again pushed citywide.
After that incident, Stacey Hervey, an affiliate professor in criminology and criminal justice at Metropolitan State University of Denver, warned that situations like these could cause people to not take the alerts seriously.
