Sirens - Dane County Emergency Management

Outdoor Warning Sirens

Outdoor warning sirens are one tool Dane County Emergency Management utilizes as part of our severe weather warning system. They are intended to be heard outside, and should not be relied upon to be heard inside a structure. Outdoor warning sirens should not be your primary source of alert for tornado warnings. Instead, NOAA weather radios, smart phone apps, and/or local broadcast media should be your primary sources of severe weather alerts.

If you hear an outdoor warning siren, refer to one of the previously mentioned severe weather alert sources to confirm the siren activation, and seek shelter immediately as appropriate. If you believe the siren has been activated in error based on the lack of supporting information from other severe weather alerting sources, please call 608-255-2345 option 6, and report the location of the siren.

Activation, Testing, and Troubleshooting

In the event of a Tornado Warning being issued by the National Weather Service, the siren activation is a three-minute steady tone. The sirens in the warning area will only sound once, at the onset of the warning, and no 'all clear' signal will be sent.

Sirens are tested year-round on the first Wednesday of every month at approximately 12:00 p.m., weather permitting. Tests also use a three-minute steady tone.

While Dane County's outdoor warning sirens are activated primarily for tornado warnings, the system will also sound for areas impacted by Severe Thunderstorm Warnings issued by the National Weather Service that carry a "destructive" tag. This tag is associated with strong thunderstorms with reports of 2.75-inch diameter (baseball-sized) hail and/or 80 mph winds.

Occasionally, a siren site will communicate an error message to the controlling software. When that happens, our siren repair contractor will conduct testing to troubleshoot the issue and administer repairs as necessary. This process may necessitate a brief audible test of the siren to confirm its operational status. Because of the urgent need for this testing, the very short duration of the audible test, and the intrusive nature of a large area notification, Dane County Emergency Management does not notify area residents prior to audible testing.

Dane County Emergency Management will not conduct testing during threatening weather or after dark. Please contact Dane County Emergency Management at 608-266-4330 during normal business hours if you have questions regarding this process.

Siren Location Maps

There are 144 outdoor warning sirens in the Dane County system. The sirens are located in the most densely populated areas of the County. As the outdoor component of the warning system, the sirens have a very important role; they are an effective means of alerting people who are outside and within range.

Click on the map to see a larger version of the image.

Siren Map (PDF)

Dane County Siren List (PDF)

Siren Effective Range

The circles on the map indicated the estimated OUTDOOR effective range of the sirens. The ranges are shown for planning and comparison purposes only. These ranges do not necessarily represent the actual audibility of any given siren.

There are a number of factors that affect the range of the siren. First of these is sound output. Very simply, some sirens are designed to be louder than others. A louder siren will have a greater range.

Atmospheric conditions also affect siren range. Wind speed and direction, air stability, and relative humidity all affect the distance that the sound will travel. Your ability to hear the siren will change as these conditions change. It is very possible that from your location, in some cases you will be able to hear the siren, while in other cases, you won’t.

Topography and background noise levels will also affect your ability to hear the sirens. Hills, trees, and buildings can be barriers that block the sound. High background noise levels from highways or industrial areas can mask the sound of the siren. These conditions will effectively limit the warning range of the siren.

Even with these limitations, sirens can be a very effective source of warning, if you are outdoors and within range of the siren.