Siren tests are not conducted during December, January and February due to winter weather.
Siren Activation Policy Includes Severe Thunderstorms
As we all know, a severe thunderstorm with straight line winds of 70 mph or greater can do as much damage as a weak (EF0) tornado. Oakland County Emergency Response and Preparedness now activates the County's Outdoor Warning sirens for tornados and severe thunderstorms with damaging winds at/near 70 mph or greater in Oakland County and within a ten mile buffer around the County (this will give citizens living close to the border more time to take cover).
In the past, the outdoor warning sirens were only activated when a tornado was sighted or strongly indicated on radar. This change in policy is a result of the tornado touchdown in Holly in 2007 and the severe thunderstorm with damaging 80mph winds in early June of 2008.