Emergency Alert and Warning Tools

Information regarding publicly available emergency alert and warning tools

Public Emergency Alert and Warning Tools – All of these tools are available to the Marin County Sheriff’s Office of Emergency Services (OES) to warn residents and visitors in Marin County about threats to life and property. We use these tools at the direction of incident commanders and tailor use of the notification tool to the incident/disaster.

Emergency Alert System (EAS)

The Emergency Alert System  (EAS) is used by alerting authorities to send detailed warnings via broadcast, cable, satellite, and wireline radio and television channels. EAS provides very broad alerting to the entire Bay Area media market. Anyone not watching / listening to broadcast media will not get the message. EAS Participants-radio and TV providers nationwide-are the stewards of this important public service in close partnership with alerting officials at all levels of government.

In many cases, radio and TV stations continue to operate when other means of alerting the public are unavailable, providing a layer of resiliency to the suite of available emergency communication tools. FEMA, with support of the Federal Communications Commission (FCC), is responsible for implementation, maintenance, and operation of the EAS at the Federal level. The Marin County Sheriff’s Office of Emergency Services (OES) is an approved “alerting authority”

Wireless Emergency Alerts (WEA)

Wireless Emergency Alerts (WEA) are short emergency messages from authorized public alerting authorities that can be broadcast to any WEA-enabled mobile device in a locally targeted area. The WEA channel can be used for three alert categories: Presidential, AMBER, and Imminent Threat. WEA messages are broadcast from cellular towers in the designated alert area to any WEA-enabled mobile devices that communicate with the cell tower during the alert duration. Wireless carriers primarily use cell broadcast technology for WEA message delivery. WEA is a partnership between FEMA, the Federal Communications Commission (FCC), and wireless carriers, to enhance public safety.

Unique Ring Tone & Vibration: WEAs automatically “pop up” on the mobile device screen and are limited to 90 characters. WEAs use a unique ring tone and vibration designed to draw attention and alert people to an emergency. The unique vibration, which distinguishes the alert from a regular text message, is particularly helpful to people with hearing or vision-related disabilities.

Geo-targeted alerts: WEAs are targeted to the specific geographic area of the emergency. Due to the nature of cell tower technology and coverage the targeting often results in broad alerting for an entire county or a large portion. “Bleed over” will often cause alerts to go beyond the target area – potentially beyond Marin. If a WEA-capable mobile device is physically located in that area, it will automatically receive and display the message.

Non-subscription based: WEAs are not subscription based, so customers of participating wireless carriers with WEA-capable phones do not sign up to receive the alerts. Instead, they automatically receive WEAs if a WEA is active in the area in which they are located. Wireless customers are not charged for the delivery of WEA messages and may opt-out of Imminent Threat or AMBER alerts, but may not opt-out of Presidential alerts.

Avoids congestion: WEAs use SMS-Cell Broadcast (SMSCB), a one-to-many service, which simultaneously delivers messages to multiple recipients in a specified area. By using SMS-CB as the delivery service technology, WEAs avoid congestion issues experienced by traditional voice and text messaging (SMS-PP) alerting services, which translates into faster and more comprehensive delivery of messages during times of emergency. All the major U.S. cell carriers are participating in WEA on a voluntary basis. Wireless carriers are currently selling mobile devices with WEA capability included; however, not all handsets currently on the market are capable of receiving WEAs. It is anticipated that most commercially available phones will be WEA-capable in the near future. To find out what mobile devices are capable of receiving WEAs check with your local cell provider.

The Marin County Sheriff’s Office of Emergency Services (OES) is an approved “alerting authority” for WEA alerts.


The Marin County Sheriff’s Office of Emergency Services (OES) uses the AlertMarin  Emergency Notification System to deliver incident-specific information or potentially life-saving instruction to the precise geographic area(s) affected. Emergency situations may include:

  • flooding, wildfires, and subsequent evacuations;
  • public safety incidents including crimes that affect your neighborhood;
  • post-disaster information about shelters, transportation, or supplies.

If you live, work or go to school in Marin County and are 18 and over, you may now register your cell phone or VoIP (voice over internet protocol) phone to receive emergency alerts sent by call, text, email, or smartphone application from the County of Marin. Search the Apple Store or Android Marketplace for the “Everbridge” app.

Listed and unlisted/blocked Marin County landline phone numbers are already included in our emergency notification system. Cell phone and VoIP numbers are not included and will require your registration in our Self-Registration Portal @ alertmarin.org.


Nixle is a Community Information Service dedicated to helping you stay connected to the information that matters most to you, depending on your physical location. You stay connected to your local police department ensuring that you receive trusted and immediate, geographically relevant information. Information is immediately available over your cell phone by text message, by email, and over the web. Members of the public may self-register by texting their zip code to 888777. The system typically alerts via SMS / text, though email & smartphone app. Alerting can be geographically focused from a single zip code to entire county.

Your account can be customized so you receive the information that matters most to you. Whether it is where you live, work, or have friends or family throughout the country, the information is immediately available to you over your mobile phone, email and computer. Only authenticated agencies and community organizations can securely publish information. There are multiple agencies in Marin County that use Nixle including the Marin County Sheriff’s Office.

There are four types of messages; Alerts (many would refer to this as an emergency type alert), Advisories (less urgent need-to-know information), Community Information (day-to-day neighborhood to community-level information), Traffic (very localized traffic information).

Anyone can view information by going to www.nixle.com without registering. However, to customize the information you receive and the locations you receive it from, in addition to receiving information by text message and/or email you must set up an account. Once registered, you can personalize your locations and your preferences, making the service fit your needs.

Social Media

The Marin County Sheriff’s Office uses many of the social media platforms now available to assist in disseminating information to the public. These platforms are: Twitter, Facebook, Nextdoor, Instagram, Webpages and others. We use these platforms to share all kinds of information from non-emergency to emergency. We do not rely on these platforms alone to convey urgent emergency alert and warning messages. We may use them to share additional information regarding an ongoing incident after the appropriate warning has already been broadcast through one of the preferred alert methods above.


Some communities in Marin County use sirens or horns to alert residents and visitors to an imminent dangerous situation. The siren/horn activation is usually followed up by the distribution of additional information or direction by using one of the alerting systems above or by broadcasting a pre-recorded message on a local radio station. These sirens or horns are location specific but the sound often “bleeds over” into adjoining jurisdictions therefore neighboring jurisdiction work together to coordinate messaging.

Weather Radios

Weather Radios can be a great option during an extended power outage (over ~ 4 hrs) which causes cell phone towers to stop working.  This happens often during PG&E PSPS events and can happen during flooding or after an earthquake.  More information is available by clicking HERE

Law Enforcement/Fire Agency Evacuation Procedures

Law Enforcement Officers and Firefighters may drive through neighborhoods with sirens activated announcing evacuations and/or emergency directions over their loud speakers. Sheriff’s Air Patrol may also fly overhead announcing the same information