Only one tornado siren in Wausau failed Thursday's drill, according to the city inspector.

He says the siren at John Marshall Elementary School did not sound, but crews are scheduled to work on it Friday.

Over the course of a long winter, the inspector says quirks can develop in the system, which is why the sirens are tested.

The sirens are typically tested once a month in winter, but during severe weather season they are tested each Monday at 1 p.m.