These sirens are part of the Oakland County Early Weather Warning Program.
When the National Weather Service issues a tornado warning or a severe thunderstorm with damaging winds at or greater than 70 mph, the sirens are activated from the Oakland County Dispatch Center which is manned 24 hours a day.
Please be advised that Oakland County Emergency Management will be testing the outdoor warning siren system on the following dates in 2015:

 

March 7 Saturday 1pm First Saturday of the Month
April 4 Saturday Cancelled Due to SWAW test week
April 15 Wednesday 1pm Special test in recognition of Severe Weather Awareness Week (SWAW)
May 2 Saturday 1pm First Saturday of the month
June 6 Saturday 1pm First Saturday of the month
July 4 Saturday 1pm First Saturday of the month
August 1 Saturday 1pm First Saturday of the month
September 5 Saturday 1pm First Saturday of the month
October 3 Saturday 1pm First Saturday of the month
November 7 Saturday 1pm First Saturday of the month

Note: Siren tests are not conducted during December, January, or February due to winter weather.