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.
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.
