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Hennepin county

Preparing for extreme weather

An outdoor warning siren.

Hennepin County is upgrading the control system that operates nearly 300 city‑owned outdoor warning sirens across the county. This work is modernizing the state’s largest coordinated outdoor alarm system, one of the largest in the country, to provide faster, more precise and reliable warnings during emergencies.

The upgraded system will reduce alarms that reach areas not directly at risk and will give technicians better real‑time data about system performance. These improvements help ensure the sirens are ready when residents need them most.

Testing during the transition

As this work moves forward, the Hennepin County Emergency Management team will spend several months testing the new system. The current control system will stay in place until the new one is fully functioning, and both will run at the same time during the transition. Monthly siren tests at 1 p.m. on the first Wednesday of each month will continue, and residents should expect them to sound the same as usual.

During the upgrade period, residents may occasionally hear short growl tests that last 10 to 15 seconds. These brief checks help technicians confirm that individual sirens are working properly. Cities and the county will share notifications when these tests are planned. Some residents may also notice small differences in how the monthly sirens sound or the timing of the alerts. These changes are normal parts of the testing process.

What to do when you hear a siren

Sirens are an indication to take action quickly by finding a safe location and confirming what type of emergency is occurring. When outdoor warning sirens sound, your next step should be to move indoors immediately, stay away from windows and check trusted alert sources such as weather apps, local news or NOAA Weather Radio for additional information.

More than one way to get alerts

Outdoor warning sirens play an important role in alerting people who are outside, but they are only one part of a reliable emergency warning system. The county encourages residents to have multiple ways to receive alerts. Options include:

  • Warning apps (such as Red Cross Mobile Apps)
  • Portable radios tuned to local stations
  • Local broadcast and cable television
  • "Weather radio" alarm monitoring system

Many devices offer accessibility features for residents with hearing or vision challenges. Twin Cities PBS’s “TPT Now” service also provides immediate alerts in English, Spanish, Hmong and Somali.

Staying prepared all year

Even with a modernized siren system, emergency preparedness is a shared responsibility. Extreme weather can develop quickly in Minnesota, and residents play an important role in staying ready throughout the year, not just during the monthly siren test. Helpful steps include:

  • Reviewing your family’s emergency plan
  • Identifying safe indoor shelter locations at home and work
  • Keeping phones and backup power sources charged
  • Maintaining basic emergency supplies
  • Monitoring weather forecasts regularly

Strengthening emergency preparedness countywide

Hennepin County continues to work closely with cities, the National Weather Service, and partner agencies to strengthen public warning systems. Upgrades like this siren modernization improve accuracy, speed and reliability and support a safer community.

When the county and residents stay prepared together, everyone is better protected.

Learn more about Hennepin County outdoor warning sirens and how to stay prepared.