Chicago Weather

Illinois Tornado Sirens: How and When They're Activated and Emergency Tips

Illinois residents are all too familiar with the shrill tone of a tornado siren, but they may not be as familiar with all of the situations when those sirens are activated, and how often they are tested.

Here is a list of frequently asked questions about Illinois’ emergency warning system, and tips that residents can use to protect themselves in the event of severe weather.

When is a Tornado Warning Issued?

A tornado warning can be issued by the National Weather Service in two scenarios. The first is when there has been a tornado observed by trained weather spotters on the ground, and the other is when Doppler radar indicates rotation within a storm that could spawn a tornado at any time.

The latter scenario is one that officials have made it a point to warn residents of, urging them not to wait until they see a tornado before seeking shelter.

A tornado watch is issued when conditions are favorable for the development of tornadoes. Sirens do not sound when a watch is in effect, and residents don’t necessarily have to seek shelter during a watch.

Who Activates the Sirens?

In most cases, local authorities, such as police or fire departments or local emergency management agencies, are responsible for activating tornado sirens.

According to the University of Illinois, some sirens can be activated using “Common Alerting Protocol,” which allows sirens to be activated automatically in the event of a National Weather Service warning.

Others require sirens to be manually activated, but the procedure varies by community.

Are There Other Scenarios Where Sirens Can be Activated?

Most Illinois residents associate sirens with tornado warnings (they are not sounded during tornado watches), but there are other scenarios where some communities will sound the sirens.

According to officials, high winds or large hail can also cause officials to trigger sirens, including in the Quad Cities and other parts of the state.

The sirens can also be used in the event of a national emergency, including a military attack or a chemical attack, and those alerts will use a different tone, which can be heard on the Illinois Department of Homeland Security’s website.

What Else Do Community Officials Recommend?

Officials are quick to remind residents that sirens are only designed to be heard outdoors, and that they should take other precautions to ensure that they have the latest weather information.

While many smartphone apps can provide that information (including the NBC 5 app), officials also recommend keeping a battery-powered radio handy if at all possible.

NOAA Weather Radios are also available, and essentially function like a “smoke detector” for severe weather, automatically powering on when an alert is issued.

Aside from those tips, officials also recommend that residents put together a storm preparedness kit that includes essentials like flashlights, batteries, blankets and clothing. Items like waterproof matches, a paper and pencil, cash, and extra water can also be included in the kit.

For a full list of suggestions, residents can visit the Ready Illinois website.

How Often Are Sirens Tested?

Sirens in Illinois are tested on the first Tuesday of each month at approximately 10 a.m. If the possibility of severe weather exists on that date, then the test can be moved at the discretion of local officials.

Do Communities Still Use the Sirens to Signal an “All-Clear” Situation?

According to DHS and the NWS, most communities in Illinois no longer use sirens to signal an “all-clear,” but it varies by area, so check with local emergency management officials for more information.

Contact Us