Outdoor Warning Sirens
When Do They Sound
The sirens may be activated for several reasons, including but not limited to the following:
- The National Weather Service issues a Severe Thunderstorm warning that includes Coppell and contains a phrase indicating that
- Destructive winds in excess of 70 miles per hour or higher are likely with the storm
- Destructive hail, 1.5 inches or larger is likely
- Catastrophic emergencies that pose an immediate threat to safety (i.e. dam failure)
- Hazardous materials emergency
- Local Warning Point activation in coordination with the National Emergency Alert System
- Monthly testing
- The National Weather Services issues a Tornado warning that includes the city of Coppell
- Tornadic activity is reported by a reliable source in or approaching the city of Coppell
How They Work
On any given day, during an emergency or for testing purposes, Coppell's OWS are activated from the Coppell Emergency Operations Center located in Life Safety Park.
Each activation of the OWS is 3 minutes in duration. There is no "all clear" signal so just because the sirens stop, that does not necessarily mean that the threat has passed. It is common during a prolonged threat for the sirens to sound a 3-minute activation followed by several minutes of silence and then the cycle is repeated for the duration of the threat.
There are two tones used during siren activations, but both are a prompt to seek shelter and seek information:
- A Steady Single Tone is the most common and is used for local emergency warning activations like Tornado warning.
- The "Alt-Wail" Wavering Tone is used for national warning activations.
- The system is also capable of voice public address and may be used city-wide in exigent circumstances.
What to Do When You Hear Them
When the Outdoor Warning "Siren" System activates - stay calm, immediately seek shelter inside and seek information. Listen to the NOAA All Hazards Weather Radio or local television/radio stations for additional information and specific instructions. Remain indoors until the emergency has ended or directed otherwise.
As the name implies, the Outdoor Warning System is intended to warn people outdoors. It is not intended nor designed to provide adequate warning in your home or other indoor locations. Always have more than one means of receiving emergency alerts!
When They Are Tested
Weather permitting, the City of Coppell audibly tests the OWS sirens on the first Wednesday of each month at 1 pm. The test includes a Steady Single Tone that lasts for 3 minutes.
The City also performs a "quiet test" of the system twice daily. The system activates all functions of each siren short of actually generating the tone. The system automatically notifies emergency management staff of any faults in the system. This functionality helps to assure that the sirens are maintained in working order.