The city of Denver was under a tornado watch Monday afternoon — but the hazard sirens that howled just after 4 p.m. were a mistake, city officials said.
"Siren was sounded inadvertently. There is no threat of destructive weather to Denver at this time," wrote mayoral spokesperson Jon Ewing.
The area still faces a general risk of hazardous weather. The tornado watch — which indicates that weather conditions may produce tornadoes — was expected to remain in effect until 9 p.m. It also covers points north toward Greeley, south toward Douglas County, and east to Kansas.
“We're mostly looking at a larger hail threat today on top of a few tornadoes,” said Greg Heavener, the warning coordination meteorologist for NWS Boulder and Denver. “The main threat for the storms today is very large hail, upwards of 2- to possibly 4-inch diameter hailstones, possibility of a tornado or two also as we get from the metro area out towards the Eastern Plains of Colorado.”
NWS also issued severe thunderstorm warnings for parts of the metro.
"We understand that unexpected siren activations can be concerning and appreciate the public's patience and understanding. The cause of the inadvertent activation is being reviewed, and appropriate steps will be taken to help prevent similar incidents in the future," wrote Loa Esquilin-Garcia, a spokesperson for the city's Office of Emergency Management, in an email.
On Tuesday, Esquilin-Garcia added that the siren sounded because of "human error and an improper understanding of protocol."
As she wrote: "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 siren activation process is managed by authorized personnel within the City’s emergency operations structure. The staff member does work in person."
She continued: "As a result, the city is implementing corrective actions, including a comprehensive review of alerting policies and procedures and enhancements to training and exercises for personnel involved in emergency alerting and warning operations. The City and County of Denver recognizes that emergency alerts are intended to prompt immediate action during potentially life-threatening situations, and any unintended activation is a serious matter. 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."
Kiara DeMare and Paolo Zialcita contributed to this article.
Editor's note: This article was updated with further comment from the city. A sub-headline in this article was corrected to note that the area was under a tornado watch, not warning.
