Outdoor Warning Sirens

Do not call 911 to ask why the warning sirens have been activated. Only call 911 if you have an emergency to report for Police, Fire or EMS assistance. Contact Rowlett OEM at 972-412-6230 for answers to questions regarding sirens and siren activation.

The City of Rowlett has an all-hazards system of ten Outdoor Warning Sirens that are strategically located around the City to alert citizens, who are outdoors, of approaching or existing hazardous conditions.

Outdoor Warning Sirens

Because they are often associated with tornado warnings, Outdoor Warning Sirens are often considered "tornado sirens;" however, the term "tornado siren" is a misnomer that fails to capture the fact that these sirens serve as an all-hazards alerting system. Outdoor Warning Sirens may be activated for:

• Tornado Warnings and Tornado Emergencies issued by the National Weather Service
• A tornado or funnel cloud reported by reliable, official sources (e.g., public safety personnel and trained storm spotters)
• Sustained winds in excess of 70 mph
• Verified reports of ping-pong ball (1.5"), golf ball (1.75") or greater sized hail for the City of Rowlett
• Hazardous material (HazMat) spill or chemical release emergencies
• Other emergencies as appropriate

Sirens are not activated by an automatic system. Instead, an authorized City official must determine whether or not to activate the sirens based on the current threat(s). Additionally, the City is capable of activating individual sirens when a multi-siren or system-wide activation is unnecessary due to the limited geographical impact of a hazard.

What To Do When A Siren Sounds

If you hear a siren:

• Remain calm
• Make sure that it is not a siren test (see below for more information)
• Seek sturdy shelter immediately
• Make your way to an interior room, away from windows and exterior walls
• Turn on a radio or television to a local station for more information about what the specific hazard is (check your mobile device for any alerts from the NWS or  https://www.smart911.com/smart911/registration/registrationlanding.action Connect Rowlett)
• Pay careful attention to any instructions
• Take action, especially any that is recommended by official sources, to protect yourself and your family
• Unless told otherwise, stay indoors until the emergency has ended

Do not call 911 to ask why the warning sirens have been activated. Only call 911 if you have an emergency to report for Police, Fire or EMS assistance. Contact Rowlett OEM at 972-412-6230 for answers to questions regarding sirens and siren activation.

Monthly Testing

The Outdoor Warning Sirens are tested on the first Wednesday of every month at 1:00 PM. The sirens are tested with a three minute blast that will fade in and out as the sirens rotate.

The sirens are not tested during periods in which severe weather is possible, in order to avoid confusion between actual severe weather and testing. A modified test, known as a "growl test," may be performed when overcast, and virtually no chance of severe weather exists. A growl test is simply a very low volume test. Additionally, growl tests may be used to test sirens after an initial test or when testing sirens outside of the regular date/time.

Siren tests from surrounding jurisdictions may also be possible:

• Dallas - 12:00 PM on the first Wednesday of every month
• Garland - 12:00 PM on the first Wednesday of every month
• Rockwall - 2:00 PM on the first and third Wednesday of every month
• Sachse - 12:00 PM on the first Saturday of every month
• Wylie - 1:00 PM on the first Wednesday of every month

Siren tests and test cancellations are typically coordinated with surrounding jurisdictions.

Limitations Of Outdoor Warning Sirens

It is important to understand that these sirens are designed to alert those who are outdoors, and are not intended to alert people in cars, homes, businesses, or other buildings. It is possible to hear sirens indoors, but it should NOT be expected.

It is also possible that you may not hear activated sirens when outdoors. Several factors affect the audible range of sirens, including:

• Sound frequency
• Atmospheric conditions
• Topography
• Ambient noise levels
• Proximity to activated siren(s)

The City’s new OWS system is designed to provide 70 decibel (a FEMA standard; equal to a common household vacuum cleaner) outdoor warning coverage across the City. The City uses a “WAIL” tone operating between 410-675 Hz and a “WHOOP” tone operating between 300-465 Hz. These non-steady tones allow for an easier tone perception, compared to steady tones, by those outside.

The new OWS system is comprised of six-cell and ten-cell sites. The six-cell sites are designed to provide a tone output of 2400 watts and a voice output of 3000 watts. The 2400 watts provide an estimated 70dB coverage radius of 4,800 feet. The ten-cell sites are designed to provide a tone output of 4000 watts and a voice output of 5000 watts (the voice feature on the ten-cell sites will not be used for primary outdoor warnings). The 4000 watts provide an estimated 70dB coverage radius of 6,100 feet.

Sound Sample Requests

If you believe that the siren output at your Rowlett residence or business location is below the designed 70dB OWS system minimum, you may request that Office of Emergency Management staff collect a sound sample from your property. Please email requests to oem@rowlett.com. 

A sound sample will only be collected:

• during the monthly sound test
• from a publicly accessible location
• if the requested location is more than 100 feet from a sound sample collected within the previous twelve months
• upon staff and equipment availability

Sound sample results will be emailed to the requesting party and posted on the City's OWS Sound Sample Results webpage.