DU-COMM has identified what caused tornado sirens to blare twice in one week across Hinsdale and is removing the faulty equipment.
DuPage Public Safety Communications released its investigation findings Wednesday, Aug. 26, pinpointing the root causes of both false activations that rattled residents on Aug. 18 and Aug. 21, Patch reported.
The first activation, around 10 a.m. Tuesday, Aug. 18, was straightforward: an employee error during a planned test of background warning systems. DU-COMM staff shut the sirens off as soon as they realized the mistake.
The second, around 3 a.m. Friday, Aug. 21, woke residents across the county. No storm was in sight. DU-COMM's investigation found a malfunctioning device in the chain of components that control the outdoor warning sirens triggered the activation on its own. The agency said it found no evidence of human error or malicious intent.
DU-COMM and its equipment vendors have enacted a plan to remove that device and simplify the system, eliminating the failure point. The agency said it is continuing to review the technology and protocols involved in both incidents.
How the community responded
On Tuesday, Aug. 18, Hinsdale Village President Greg Hart posted on X to reassure residents there was no severe weather threat and that DU-COMM had confirmed the accidental activation. Hinsdale Police Chief Brian King told The Hinsdalean on Aug. 20 that resident calls prompted the department to share DU-COMM's apology.
"We got a couple of inquiries the next morning, which is why we put out the release," King said at the time.
The Aug. 18 false activation was countywide, affecting many towns beyond Hinsdale. The National Weather Service confirmed it did not trigger the alert.
What residents should do
DU-COMM advises anyone who hears a tornado siren to take shelter immediately and verify whether a real threat exists through the National Weather Service or NOAA Weather Radio. The agency launched an automated siren activation system in May 2025 that triggers sirens faster when a genuine warning is issued.
