Have Multiple Ways to Get Alerts & Warnings
It is important to have multiple ways to receive weather alerts & emergency information.
NOAA Weather Radios are one of the fastest and most reliable way to get weather updates and warnings.
Alert Hamilton County – Sign up for severe weather alerts, life-safety information & emergency messages at www.alerthc.org.
Wireless Emergency Alerts (WEAs) are based on your current location & will alert you anytime you are inside an “ExtremeWeather Warning” area – Tornado Warning or Flash Flood Warning. Check the “Notification”settings of your smartphone to enable WEAs.
The Emergency Alert System transmits weather, emergency and safety information to radio and television stations.
Social Media – Follow Hamilton County EMHSA on Facebook, Twitter, Instagram and on the Nextdoor App for preparedness information. Emergency information available on Twitter & Facebook.
EMHSA App – Download the EMHSA app in the App Store and Google Play to receive push notifications about severe weather & emergency information, and to check weather & traffic conditions.*
Designed as an Outdoor Warning System, the sirens SHOULD NOT be relied upon to provide sufficient warning INDOORS or in NOISY AREAS. Additionally, 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. Because the sirens are constantly exposed to the elements and other hazards, Hamilton County EMHSA cannot guarantee that the sirens will function correctly. For these reasons, everyone is encouraged to have multiple ways to receive information about severe weather.Activation Criteria
There are three basic criteria that Hamilton County EMHSA uses to activate the sirens:
- The National Weather Service (NWS) issues a Tornado Warning for Hamilton County.
- 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 the public to seek shelter indoors 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.
Siren Test Cancellation Criteria
Basic criteria for cancelling the activation of the Outdoor Warning Sirens include:
- Extreme cold, freezing rain/drizzle, and/or icing that may damage the equipment.
- Presence of severe weather (or potential severe weather) occurring in the local area, which may cause confusion as to whether the activation is a real event.
Monthly Testing:
The Outdoor Warning Siren System will be tested on the first Wednesday of each month at 12:00 PM, unless there is inclement weather in Hamilton County. A siren test will consist of a single siren tone, lasting approximately 1 minute. Hamilton County EMHSA will notify the public via press release and social media posts when a siren test is planned, cancelled, or rescheduled, prior to the time at which the sirens will sound.
If Hamilton County is experiencing severe weather prior to 12:00 PM on a scheduled test day, the siren test may be postponed, to the determined alternate test day, which is the second Wednesday of the month, at 12 PM. Testing for the alternate day will consist of a “Growl” test. A “growl” test is a quick sounding of the sirens, lasting approximately six seconds, which tests the activation and rotation of each siren. If testing the sirens on the alternate day is also canceled, the Outdoor Warning Siren tests will resume on the next scheduled monthly date.
Siren testing may be suspended during the winter months (December – February) when ice or sub-freezing temperatures could damage the siren system. If there is an emergency during winter months, the sirens will be activated to notify people of the need to seek shelter.
If testing is required at any time outside of the normal monthly testing schedule, Hamilton County Emergency Management and Homeland Security Agency will be sure to notify the public via social media posts and press release.
*EMHSA App
By downloading the EMHSA app, you can receive push notifications about weather alerts and warnings, check weather and traffic conditions, and view Hamilton County EMHSA events.
Download the EMHSA App on the App Store.
Download the EMHSA App on Google Play
Understand Tornado Alerts
What is the difference between a Tornado Watch and a Tornado Warning issued by the National Weather Service?
- Tornado Watch: Be Prepared! Tornadoes are possible in and near the watch area. Review and discuss your emergency plans and check supplies and your safe room. Be ready to act quickly if a warning is issued or you suspect a tornado is approaching. Acting early helps to save lives! Watches are issued by the Storm Prediction Center for counties where tornadoes may occur. The watch area is typically large, covering numerous counties or even states.
- Tornado Warning: Take Action! A tornado has been sighted or indicated by weather radar. There is imminent danger to life and property. Move to an interior room on the lowest floor of a sturdy building. Avoid windows. If in a mobile home, a vehicle, or outdoors, move to the closest substantial shelter and protect yourself from flying debris. Warnings are issued by your local forecast office. Warnings typically encompass a much smaller area (around the size of a city or small county) that may be impacted by a tornado identified by a forecaster on radar or by a trained spotter/law enforcement who is watching the storm.
