The sound of tornado sirens is a signal that the tornado is near and the threat is severe. These signals are a very effective way to warn people in the short term, but only when used in combination with other communication methods such as television, radio and NOAA weather radio.
The directional type of siren directs the full decibel output towards the target location. A directional siren is often more effective than a rotational siren because it can cover a wider area.
A supercharged siren has a special source of air that forces more pressure into the rotor assembly, increasing the sound output of the siren. This increases the sound range and makes it easier for people to hear.
If a tornado warning is issued, the general alarm consists of a continuous tone that rises and descends for a minute, ending when it stops. When the alarm stops, people should take shelter immediately.
The testing alarm is shorter than a general alarm and may be a flat tone. When the test alarm stops, people should take shelter immediately and get more information about the storm.
Hamilton County operates 75 outdoor warning sirens in various locations throughout the county. They are positioned roughly one-half mile from each other to provide coverage to the general public.
In addition to the outdoor warning sirens, Hamilton County EMA also uses a number of indoor warning sirens located in schools and offices. These are used to sound when the local office of Emergency Management has received a tornado warning from the National Weather Service.
