DENVER — Every year, Denver's Office of Emergency Management tests its all-hazard outdoor warning siren system, which is designed to let anyone who's outside know they should seek shelter immediately.
"We do a full volume test once a year, and this test is to make sure the system works, but also just make sure folks understand what the sirens are," said David Powell, the deputy director for Denver's Office of Emergency Management (OEM). "The sirens exist to warn people outside that there is a hazard, and to seek shelter inside and seek more information when the sirens go off, check your cell phone for a Wireless Emergency Alert which can provide more information."
In Denver, there are 86 sirens, 11 of which are located at Denver International Airport.
- Listen to the sirens in the video player below
"They can be activated by radio activation, they have a battery so they can operate if there's an interruption to power or other issues like that," Powell said. "When they are activated, they will spin around and have a solid sound for three minutes."
This year, Powell says OEM may use the sirens "more frequently, including during destructive storms and catastrophic flash floods, not just during tornado warnings."
"We've been trying to expand the use of the sirens, just to make sure we are providing every possible warning tool to the public when there is an actual hazard," Powell said. "Specifically, we're adding some more automated activations, for example, for the most destructive type of severe thunderstorms. If there's a thunderstorm that has very large hail or very high winds, that could be really that threat to life, not every severe thunderstorm, just the most impactful ones, the sirens will sound. We are expanding that, just to make sure we are warning the public as best we can for those bigger, more impactful threats to life."
The decision of when to use the sirens requires teamwork with other city departments and especially the National Weather Service, according to Powell.
"They are the authority for issuing those severe thunderstorm warnings, and they have within that severe thunderstorm warning kind of two tiers. The upper tier, the more destructive, the more dangerous storms — those are the ones we'll issue it for," Powell said. "They make that determination based on things like wind speed, size of the hailstones, and then we take that information and we're working with our siren software to then automatically activate the sirens after that."
Meanwhile, inside a room the OEM refers to as its "bunker", is a team of personnel who monitor the sirens and at least one person who is tasked with "pushing the button" for the sirens, should that moment come.
On Tuesday, that was Courtney Bernet, a senior emergency management specialist with Denver's OEM.
"Day to day, I am one of the folks who writes emergency plans for the city," Bernet said. "As a part of my job, I'm also one of our 24/7 rotating duty officers."
The duty officer is typically tasked with pushing the button that sets the system of sirens off in Denver, according to Bernet.
"There's always a little bit of stress with the nature of what we do, it's a little bit of our personalities that got us into emergency management, and we know that we're doing everything in our power to make sure that we're ready to press the button when we need to, and that we're ready to notify the public to make sure that they are safe and able to take whatever actions they need to to stay safe," she added.
Denver7 reached out to the Denver International Airport about the most recent times the sirens have been used there. A spokesperson provided the following list of "the latest tornado warnings that included DEN property":
- May 10, 2023
- June 12, 2022
- August 5, 2022
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