04/02/2026
Information about the City of Knox City’s Outdoor Warning Sirens:
An Outdoor Warning Siren (OWS) system consists of siren(s) designed to alert people of approaching or existing hazardous conditions, which will require immediate protective actions in order to save lives. Traditionally, these systems have been referred to as “tornado sirens” but the term fails to acknowledge all applications for activating the way sirens as directed by the National Weather Service. In order to avoid any confusion as to the purpose of these systems, the The City of Knox City refers to the sirens as “Outdoor Warning Sirens” in an effort to reinforce the multiple conditions for which the City of Knox City may activate sirens to alert people in OUTDOOR areas.
Here are some things to know about Outdoor
Warning Sirens:
* Sirens are for outdoor warning purposes and are not meant to be heard indoors.
* Hearing a siren is a signal to get indoors and seek additional information.
* If a siren stops, it does not mean the threat has ended.
Reasons for Activation
The City of Knox City may use the Outdoor Warning Sirens to alert and notify people in outdoor areas of emergency situations. Although the typical use of these systems has been to notify people of potentially dangerous weather conditions, there are several reasons why public safety personnel could activate outdoor warning siren systems. Some of these reasons include:
• Severe Weather capable of producing effects that are hazardous to persons or property
• Local Warning Point (the Knox County Central Dispatch) activates in coordination with the National Emergency Alert System
• Hazardous materials released into the atmosphere
• Catastrophic emergencies that pose an immediate threat to safety (i.e. large wildfire approaching town)
Activation Considerations
The City of Knox City may consider activating the Outdoor Warning Siren Systems when the following conditions are observed or predicted in their area:
• The National Weather Service (NWS) issues a Tornado Warning. The Outdoor Warning Siren System will be activated when the National Weather Service issues a polygon for the tornado warning to include the City of Knox City or the immediate surrounding area. The Outdoor Warning Siren System will activate for three (3) minutes to provide warning to the community. There may be times that the City activates the siren system more than once to provide advanced warning, when possible.
• The National Weather Service Issues a Severe Thunderstorm Warning and indicates the potential for destructive winds of 70 mph or greater (sustained, notwind gusts).
• Trained storm spotters have reported a tornado in the jurisdiction, or in a neighboring jurisdiction that has the potential to affect our community.
• Observed hail of 1.5” in diameter or greater. The size of hail that warrants outdoor warning siren activation may be adjusted at the discretion of local officials in the event of special situations such as large outdoor public gatherings where the potential for injury is increased.
• Other emergency as directed by the community’s designated public safety officials.
System Design and Considerations
The City of Knox City has 2 rotating electro-mechanical sirens. Rotational sirens typically employ a single output that rotates for the duration of the siren activation.
Sound propagation is affected by several factors such as vegetation, obstacles, and the insulating factors of homes, buildings, vehicles, wind and direction that the rotating siren is facing. This greatly affects the ability of people inside buildings or vehicles to hear the Outdoor Warning Siren System when activated. Therefore, it is important to know that the Outdoor Warning Siren System’s design is intended to ensure that persons who are outdoors should be able to hear the sirens. This means that persons who are indoors MAY NOT necessarily hear the sirens in their area and should utilize other means for notification such as NOAA Weather Radios, Wireless Emergency Alerts, MidlothianSafe Alerts, Emergency Notification System, radio and local television media for emergency notification. The City of Knox City currently has 2 electro-mechanical rotating sirens: 1 at City Hall and 1 at the Community Center.
Weekly Testing
The City of Knox City tests the Outdoor Warning Siren System at 12pm on Monday’s, weather permitting. The siren test will activate and run for 3 minutes to ensure that the sirens are functioning properly. The Outdoor Warning Siren System will not be tested during periods in which overcast, severe or inclement weather is possible, so as to avoid confusion between actual weather events and testing.