The Miami County Communication Center has been unable to pinpoint why Troy’s tornado warning sirens did not activate during a severe storm Feb. 20.

Center Director Jeff Busch said the process used, the settings on equipment and system functions were reviewed and the vendor tested signal strength, volume and other items.

During the annual spring statewide warning system test March 5, the sirens functioned properly, Busch said. The warning system also is tested the second Wednesday of each month.