What Are They Intended For?
Designed as an Outdoor Warning System, the sirens SHOULD NOT be relied upon to provide sufficient warning INDOORS or in NOISY AREAS. Air conditioning, thunder, wind, rain, and other conditions can cause the sirens not to be heard indoors or outdoors, even if sirens can be heard during monthly tests. Sirens are also subject to lightning strikes and other equipment malfunction. For these reasons, everyone is encouraged to have multiple ways to receive information about severe weather.
There are four basic criteria that Hamilton County EMHSA uses to activate the sirens:
- The National Weather Service (NWS) issues a Tornado Warning for Hamilton County
- A Trained and Certified Weather Spotter reports a tornado to the NWS or to Hamilton County EMHSA
- A tornado is reported by a local public safety official (police/firefighter) to the NWS or to Hamilton County EMHSA
- A dangerous situation occurs which requires citizens to seek shelter immediately
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.