When you hear Hi-Lo, it’s time to go!

We now have an additional way to notify our communities about the need for immediate evacuations during an emergency.

All of our marked police cars have been equipped with a new Hi-Lo siren. This European-style, two-tone siren makes a very distinctive and unfamiliar sound. The Hi-Lo siren will only be used for immediate evacuation notifications in a large area and during an extreme emergency. In a small evacuation situation, or where there is more time available, we will continue to use the traditional methods of making door-to-door notifications.

The Hi-Lo siren is just one more way for us to notify you during an extreme emergency in your neighborhood. The new sirens do not replace other alerting tools like Alert Marin or Nixle. Please make sure you are signed up for these alerting systems. Sign up for Alert Marin at alertmarin.org. Go to nixle.com and register to receive emails and text messages. For Nixle text messages only, text your zip code to 888777.

Please click on the video link and become familiar with the sound so that you can be better prepared. We hope we will never need to use it, but the Hi-Lo siren means one thing only – evacuate immediately.


 Alert Marin


 Alert Marin is Marin County’s Telephone Emergency Notification System.  This is a regional resource that is operated by Marin County Office of Emergency Services (OES).  Emergency officials use this system to deliver rapid incident-specific information or potentially life-saving instructions to precise geographic areas.  For example: flooding or wildfire and evacuation instructions, or public safety crime incidents immediately affecting your neighborhood.  Listed, unlisted, and blocked landline numbers provided by AT&T and Verizon are already in the emergency notification system.  Cell phone and VoIP (voice over internet protocol) numbers are not, so you need to register your cell or VoIP phone in order to receive alerts.  Alerts can be received by call, text, email, or smartphone application.   Anyone who lives, works, or goes to school in Marin County (age 18 and over) can go to the Self-Registration Portal at www.alertmarin.org   Alert Marin service is free, but text notifications may be subject to messaging charges. 

Wireless Emergency Alert (WEA)

Wireless Emergency Alerts (WEA) are short (90 character or less) messages that can be broadcast to any WEA enabled cell phone or mobile device in a locally targeted area.  These alerts may only be sent by local law enforcement agencies when there is an imminent threat of death or for an Amber Alert.  The alerts are broadcast from all cellular towers in a targeted area, to all WEA enabled mobile devises that are communicating with those cell towers.  CMPA recommends enabling the Emergency ALERTS  function on your cell phone to ensure you receive these alerts in an emergency.

In November 2017, the Federal Communication Commission ordered cellphone companies to increase emergency messages from 90 to 360 characters.

CMPA/ Fire Agency Evacuation Procedures

If the evacuation of a structure or neighborhood is necessary during an emergency, CMPA Officers and Firefighters may make personal contact with every resident if time permits.  In addition, law enforcement and fire may drive through neighborhoods and use their sirens and loud speakers to give alerts and direction.

Social Media

The Central Marin Police Authority currently uses the social media platforms Nextdoor, Twitter, and Facebook to disseminate information to our communities.  We use these platforms to share emergency and non-emergency information.  It is very important to note that we do not rely on these platforms alone to convey urgent emergency alerts for our communities

 In the event of an emergency we may use these platforms to share additional information about an incident, after the appropriate warning is broadcasted through one of the preferred methods above.  Often misinformation from well-meaning citizens is shared on social media platforms.  Community members should only trust official information shared by your government agencies during an emergency.



Nixle is a community notification system that enables public service agencies to provide alerts and messages quickly and securely to users who subscribe to the system.  Each user chooses how they want to receive information – by email.  Subscribers may select one or more areas by zip code and stay connected to important information.  Subscribing to Nixle is free however text notifications are subject to standard message rates. 

Go to www.nixle.com to register to receive emails and text messages.  Once registered you can set your preferences and select what type of information you want to receive and how.  To sign up for text messages only, text your zip code to 888777.

 How CMPA uses Nixle message types:

In the past CMPA has used Nixle texts and emails to send out all types of information, regardless of its importance and priority.  Going forward, we plan on only sending out Nixle texts when we need to issue an Alert or Advisory.  All other information will be sent out as an email under Community.  This will help ensure that when a community member receives a future text from CMPA it will receive the attention it deserves.


Emergency or critically important information where loss of life and/or property is potentially imminent.

Examples: Evacuation instructions, Wildfire, Flooding, Gas leak

Sent by text message and email.


Less urgent but important need-to-know information. Less time critical than an Alert.

Examples: Urgent police activity, Severe weather advisory       

Sent by text message and email.


Non-priority information from CMPA. 

Examples: Road closures/maintenance, news releases, event information, and news about other activities.   

Community Posting will generally be done Monday through Friday between 8:00 a.m. and 5:00 p.m. only.

Sent by email only.