Outdoor Early Warning System
The Town of Flower Mound Outdoor Early Warning System consists of eleven outdoor warning sirens located throughout the Town that are designed to inform residents who are outside of a possible emergency. The sirens may be activated individually or in small groups for a localized emergency or they all may be activated simultaneously for a town-wide emergency. The Outdoor Warning Sirens are part of an emergency system designed to provide immediate and valuable information to citizens. The system is not designed to alert those who are within a home or other structure.

What to Do if the Sirens Are Activated
If you hear the sirens while you are outside, please go inside and seek shelter immediately and refer to a television or radio for further instructions. Please do not call 9-1-1 for severe weather information. Call 9-1-1 only to report life-threatening situations. To see siren locations and ranges, please refer to the Emergency Siren Locations Map.

Siren Alerts
The sirens produce a different sound depending upon the nature of the emergency. The following descriptions provide information on the different sounds and associated function of the Outdoor Early Warning System sirens.

Siren Testing
The Early Warning System is silently tested every day to ensure that the system is functioning correctly. Audible tests of the system are performed on the first Wednesday of every month at 12:55 p.m., weather permitting.

Storms
The siren will produce a steady tone signal for three minutes. The sound will have a natural decrease / increase due to the rotation of the siren head. The sirens will only be initiated in the case of severe weather directly threatening Flower Mound as reported by the National Weather Service, a storm spotter, or a Town employee that meets at least one of the following criteria:

• Reported hail of 1.25” in diameter or greater. (1 inch may be more appropriate for areas or events where large numbers of people are outdoors)
• Rotation in a dangerous cloud or a tornado
• Straight-line winds over 70 mph

Hazardous Materials Incident
The siren will produce a slow wailing tone with 16 seconds of sound followed by 8 seconds of silence. The sound will have a natural decrease / increase due to the rotation of the siren head. Siren activation will occur if there is a significant hazardous materials incident which poses a threat to human health that will require evacuation or sheltering-in-place.

Enemy or Terrorist Attack
The siren will produce a fast wailing tone with 6 seconds on and 6 seconds off. The sound will have a natural decrease / increase due to the rotation of the siren head. Siren activation will occur if the Town is subject to an enemy or terrorist attack.