Yes. What we hear every Wednesday at noon is the test Siren and Announcement, for our Alerting and Warning System (AWS). The UC Berkeley campus siren is tested on the first Wednesday of every month. Other sirens that are tested in the Berkeley area have different schedules.
In case of a major emergency, the campus will broadcast on KALX 90.3 and will post messages at http://emergency.berkeley.edu a site which is hosted at a remote server. The campus will also make an outgoing telephone message available at 1-800-705-9998.