Temporary Outdoor Public Warning System Shutdown
Warning Siren Upgrade Project
General Questions
Q: What is the Outdoor Public Warning System and how does it work?
A: The Outdoor Public Warning System (OPWS) is a system of 119 sirens located throughout San Francisco. The purpose of the alarm system is to alert residents and visitors about critical life-safety emergencies like a tsunami, contaminated water supply or radiological attack.
In the event of an emergency, a 15 second tone will sound repeatedly for five minutes with audible instructions. If for any reason you cannot understand or hear the message being emitted over the alarm, tune into local news and radio stations, go online to www.sf72.org or a local news source or follow us on Twitter @SF_Emergency for further information and updates.
The San Francisco Department of Technology (DT) provides maintenance of the system. The San Francisco Department of Emergency Management (DEM) may utilize the system to send out alerts and warnings for critical life and safety incidents.
The last real-event use of the OPWS was on Treasure Island in 2012 due to potential water contamination on the island caused by a water main break.
Q: Why are the Sirens being taken out of service?
A: A prepared and resilient San Francisco means ensuring we have reliable and secure alert and warning systems. The Outdoor Public Warning System was taken off-line to address security vulnerabilities to an aging system m that presented a clear and immediate threat to the public safety of our city. Prior to the pandemic, the City and County of San Francisco began exploring funding options to upgrade the system to include new hardware and encryption technologies. The last upgrade took place in 2005. It remains our intention to bring the OPWS back online as quickly as funding and project implemention are available.
implementation are available.
Q: If we can do without the system for two years, is it a good use of our money to upgrade it?
A: We believe in a system with redundancy and the sirens are one of many resources used to alert the public. Other resources include text, e-mail and voicecall alerts, Wireless Emergency Alerts, the Emergency Alert System and the deployment of first responders and other emergency workers.
Alert & Warning Questions
Q: What will happen if there is an emergency? How will we receive warning?
A: San Francisco uses numerous alert and warning tools to deliver emergency notifications, alerts and warnings. During the OPWS upgrade the City retains access to several emergency notification systems outlined below. We will also utilize traditional and social media to amplify emergency alerts. In addition to these technologies, the City’s alert and warning dissemination tools include deploying first responders, disaster service workers, and community-based organizations to impacted areas to help warn residents via emergency apparatus and sirens, loudspeakers or bullhorns, and direct verbal communication. This provides redundancy for those residents who are not connected to technology to ensure that they still receive essential emergency direction, such as evacuation orders.
AlertSF – Text, E-Mail and Phone Call Alerts
AlertSF is San Francisco’s emergency notification system, that includes text message, e-mail and
phone call options. AlertSF issues life-safety alerts and instructions to subscribers following a natural
disaster; major police, fire, or medical emergency; or significant transportation disruption. There are
more than 183,000 AlertSF subscribers in San Francisco. This number is the equivalent of 51% of
households. In addition, voice alerts can utilize Yellow and White Page data to reach more than
350,000 listed phone numbers in San Francisco.
Emergency Alert System (EAS) – Radio and Television
The Emergency Alert System (EAS) is used by alerting authorities to send warnings via broadcast,
cable, satellite and wireline communications pathways. Most people recognize EAS as the weekly test
they may see on television or hear on the radio.
Wireless Emergency Alerts (WEA)
Wireless Emergency Alerts (WEAs) are used to send concise, text-like messages to WEA-capable
mobile devices during emergency situations. WEAs are sent by your state and local public safety
officials, the National Weather Service, the National Center for Missing and Exploited Children, and
the President of the United States. Most people recognize WEA as the Amber Alerts they may receive
on their phone.
Local Radio Station – KALW 91.7
KALW can be used by the City during an emergency to widely communicate response information.
This wireless communication is ubiquitous for residents and the system is tested every two weeks to
maintain resiliency.
First Responders and Disaster Service Workers
San Francisco law enforcement officers, fire fighters and other emergency workers can deploy to an
impacted area to warn residents about a threat and provide instruction. These workers would use
lights and sirens and their mobile public address systems to provide alert and warning for residents.
How to receive text alerts
The simplest way is to text your zip code to 888-777. You can sign up for more than one zip code just send them one at a time. For example, if you live in Bayview and work in North Beach, then text 94124 to 888-777. Then in separate message text 94133 to 888-777.
You can also visit alertsf.org to register for text alerts, e-mail and phone call alerts. By going online you can create a more compressive profile and customize the types of alerts you receive.
How to receive a phone call alert
AlertSF is also capable of sending voice alerts over the phone for the most critical life and safety emergencies. AlertSF has access to Yellow and White Page data and can send a voice alert to more than 350,000 listed phone numbers in San Francisco.
If you are not listed or not sure if you are listed in the Yellow or White pages you can still register your home phone by visiting www.alertsf.org.
Please keep in mind voice alerts over the phone are reserved for the most critical life and safety emergencies such as an incoming tsunami or contamination of the water system.
Q: What if the power or cell reception is offline?
A: San Francisco uses numerous alert and warning tools to deliver emergency notifications, alerts and warnings. For example, San Francisco law enforcement officers, fire fighters and other emergency workers can deploy to an impacted area to warn residents about a threat and provide instruction.
It is also important for San Franciscans to ensure they can receive emergency alerts, notifications and warnings by having a battery, hand-cranked or solar powered radio. Radio signals can continue to broadcast even when there is a local power outage.
Q: What if there is a tsunami? How will I receive warning?
A: San Francisco uses numerous alert and warning system tools to deliver emergency notifications, alerts and warnings. During the OPWS upgrade the City will still have access to AlertSF, the Emergency Alert System (EAS) and Wireless Emergency Alerts (WEA). We will also utilize traditional and social media to amplify emergency alerts. The City’s alert and warning strategies also include deploying first responders, disaster service workers and community based organizations to impacted areas to help warn residents.
People should also know nature’s warning signs: Strong ground shaking, a loud ocean roar, or the water receding are all nature’s tsunami warnings. If you’re by the water when any of these warnings happen move inland and higher ground immediately.
