Outdoor Warning Sirens

What are outdoor warning sirens?

pole with large siren mounted on top, blue sky and wispy clouds in backgroundSirens are an outdoor warning system designed only to alert those who are outside that something dangerous is approaching. Some people call them "tornado sirens" but they are used for several different reasons.

When you hear the siren, take shelter immediately!

If you hear the outdoor warning siren, TAKE SHELTER INDOORS IMMEDIATELY and seek additional information. 

DO NOT CALL 9-1-1 SIMPLY TO GET INFORMATION. Only call 9-1-1 if you need emergency rescue or emergency assistance from police, fire, or medical services. Calling 9-1-1 lines if you just want information will delay life-saving help for those in need.

What are some of the reasons sirens are activated?

  • Strong winds: 70 mph or greater
    • Most fatalities during tornadoes or severe thunderstorms happen because of falling trees or large branches, or other wind-driven debris. 70 mph is the windspeed that causes large branches and small trees to break. Find additional information about the Enhanced Fujita (EF) damage scale from NOAA.
  • Large hail: at least 1” in diameter
    • Hail begins to break windows when it reaches or exceeds golf ball size
  • Tornado: rotation indicated on radar or by official storm spotter
  • Non-weather emergency (hazmat, terrorism, nuclear emergency) that poses a threat to people outdoors and requires action to protect life

Additional Information

The outdoor warning sirens are only one part of a larger public emergency notification system. Other components include:

Remember, sirens are used to alert people who are outdoors of danger approaching. When you hear the sirens, go indoors immediately and seek more information.