Warning Siren System: what you need to know

(February 23, 2021 - Blue Ash)

ema siren snipThe Hamilton County Emergency Management and Homeland Security Agency (EMHSA) erroneously set off the warning sirens throughout the City and County yesterday.

This event had many residents questioning where to turn for information and the reasons behind siren activations. Despite yesterday’s mistaken activation, the following is the official procedure the EMHSA uses to determine when to set off the sirens.

THREE basic criteria Hamilton County EMHSA uses to activate the sirens:

  1. The National Weather Service (NWS) issues a Tornado Warning for Hamilton County.
  2. A tornado is reported by a local public safety official (police/firefighter) to the NWS or to Hamilton County EMHSA.
  3. A dangerous situation occurs which requires the public to seek shelter indoors immediately i.e. a chemical spill.

Hamilton County has the capability of activating all of the sirens at once or by activating one or more of six siren zones. All sirens are sounded unless the threat is clearly confined to an individual zone (or zones). During a tornado warning, the sirens will be sounded for a three-minute duration in ten-minute intervals (three minutes on, seven minutes off) for as long as the tornado warning is in effect. There is NO “all-clear” siren. 

The City of Blue Ash is within Zone 6.  In the case of an emergency specifically related to the City of Blue Ash, City Emergency Responders and Administrators would contact the EMHSA to have the sirens activated. If information specific to the City needed to be disseminated, this emergency information would be shared first through the EMHSA’s ALERT HC notification service (sign up here), the City’s website, City and local social media channels, and local news.

What to do when you hear the sirens:

  1. Take cover. Depending on the emergency, you may need to either get to the lowest floor of your home, the basement, or an interior room.  In some cases, you may be instructed to evacuate.
  2. Tune in. Listen to local radio, watch TV, follow local news websites and social media and wait for further instructions or updates.
  3. Take action.  When instructed you may need to board up windows and doors of your home. You may also be asked to evacuate to a safer location in the area.  

According to the EMHSA, the sirens are not meant to be heard indoors. This means people should not rely upon the sirens as their only warning system for tornados or other emergencies. That is why signing up for ALERT HC is so important. (sign up here)

For information on monthly siren testing on the first Wednesday of each month at noon and siren maintenance, click here.  

If you have additional questions, you can reach out to the EMHSA directly by emailing Sirens@hamiltoncountyohioema.org or calling 513-263-8210.