Oakland County Emergency Management tested all 275 outdoor warning sirens across the county on Saturday, Aug. 1, at 1 p.m., including sirens in Farmington and Farmington Hills.

Oakland County Government announced the test on X, directing residents to sign up for OakAlert emergency notifications. The test was routine. The county conducts siren tests on the first Saturday of every month from March through November, all at 1 p.m. No tests are scheduled in December, January, or February due to winter weather. The next test is Saturday, Sept. 5.

The three-minute tone has a specific meaning during real emergencies.

What the sirens mean

When activated for a real emergency, the steady three-minute tone means a tornado has been sighted or strongly indicated on radar, or a severe thunderstorm with winds of 70 mph or greater is in the area. The sirens are triggered when the National Weather Service issues a Tornado Warning or Severe Thunderstorm Warning with damaging winds at or above 70 mph for Oakland County.

Each siren covers about a one-mile radius. The system is designed to alert people who are outdoors. Residents inside buildings may hear the tone only if they are close to a siren location.

One detail that catches people off guard: Oakland County activates all 275 sirens countywide for any qualifying event, according to the county's emergency management website. That means sirens may sound in Farmington Hills on a clear afternoon because another part of the county is under a weather threat.

What to do when sirens sound

During a real activation, Oakland County Emergency Management says residents should seek shelter immediately and tune to local radio or television for details. The department asks that residents not call police, fire departments, or news media when sirens sound.

How to sign up for OakAlert

Because the sirens are designed to alert people outdoors, Oakland County also offers OakAlert, a free notification system that sends emergency alerts by text and email directly to residents' phones.

To sign up, text "OakAlert" to 99411 or visit the Oakland County emergency alerts page. The service is free, though standard messaging rates may apply. Information submitted is kept confidential and not shared with third parties.

Oakland County Emergency Management can be reached at 248-858-5300 or [email protected].

The remaining 2026 siren tests are scheduled for Sept. 5, Oct. 3, and Nov. 7, all at 1 p.m. If severe weather threatens on a test day, Emergency Management may cancel the test.