Mill Valley emergency siren system activates after glitch

An emergency siren system malfunction in Mill Valley caused the equipment to blast out a series of alerts on Tuesday, according to the Southern Marin Fire District.

The system improperly switched into “test mode” for reasons that are under investigation, the district said. Normally the system is tested at noon on the first Saturday of the month.

The sirens — known as a long-range acoustic devices — are at City Hall, Cascade Canyon, Blithedale Canyon and Warner Canyon, police Lt. Shaun McCracken said.