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San Luis Obispo County, California

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Public Alert and Notification

Public Alert and Notification


Early Warning System Sirens

The San Luis Obispo County Early Warning System sirens extend throughout the Emergency Planning Zone.  Although the siren system was installed primarily for an emergency at Diablo Canyon Power Plant, they can be utilized for any emergency where protective actions are necessary by the general public such as an evacuation due to a tsunami or dam failure.  When activated, the sirens will produce a steady wail for 3-5 minutes.  The siren system is an indication that the Emergency Alert System has been activated and emergency information will be provided on local radio and TV stations.

The EWS sirens are tested regularly, including twice monthly silent tests, quarterly growl tests, and a full scale annual test in late August.  No action is required on the part of the public during these tests.


Emergency Alert System

The Emergency Alert System (EAS) is a national public warning system that requires radio and TV stations to broadcast emergency information provided by local, state and federal officials.  During an emergency, local officials could activate the EAS to provide emergency information and actions necessary to the general public over local radio and TV stations.  Local radio and TV stations are an effective way to stay tuned to emergency information.  It is essential to have battery-powered devices, such as a battery operated radio to stay tuned during power outages. 

The Emergency Alert System is tested on the first Thursday of every month.


Emergency Telephone Notification System

San Luis Obispo County officials have the capability to inform the public of an emergency by utilizing an emergency telephone notification system, known as Reverse 911.  This system allows emergency officials the ability to notify residents and businesses in a designated area of an emergency and actions they may need to take.  San Luis Obispo County officials may chose to utilize this system for any emergency taking place in the county.    

The telephone notification system utilizes the 9-1-1 telephone database and therefore is able to contact listed and unlisted land-line telephones.   If you have a Voice over IP (VoIP) or cellular telephone that you would like to be notified on, you must self-register those telephone numbers.  To register, click here

The Reverse 911 system is tested throughout the Emergency Planning Zone on the fourth Saturday in August, in conjunction with the full-scale test of the Early Warning System sirens. 


Route Alerting

Route Alerting is a form of alert and notification that is used frequently in small scale emergencies or during rapidly changing situations in a designated area.  In route alerting, emergency officials drive or walk through an affected or potentially affected area alerting residents in that area of the emergency and actions they need to take. Route Alerting can be conducted door to door or via a public address system on a police car, fire engine etc.  Although route alerting is effective when other systems are unavailable, it is dependent on resource availability and can be a slow process.  Route Alerting is traditionally utilized only in areas that are ordered to take action. 


Social Media

In addition to the traditional forms or public notification, social media is an additional method that may be utilized to share information regarding the emergency.  Although emergency officials will continue to utilize the Early Warning System sirens and the Emergency Alert System as the primary alert and notification method, we welcome the public to connect with us on Facebook and Twitter.

Wireless Emergency Alerts

Wireless Emergency Alerts (WEA) are free informational text messages that are sent to WEA-enabled cellphones within range of an imminent and dangerous local situation, severe weather event or AMBER emergency. Click here to learn more.


NOAA Weather Radio

Emergency alert radio signals are provided by the National Oceanographic and Atmospheric Administration's (NOAA) National Weather Service (NWS).  These radio signals are not accessible over AM/FM radios but are received by NOAA weather radios.  Weather alert radios can be used to alert the public of other serious emergencies, not just weather events.

NOAA Weather Radios are typically available at electronic stores and online.

To learn more about these inexpensive radios at the NWS notification system, visit: