Mayor Breed and Board President Peskin Announce Citywide Outdoor Public Warning System Upgrade

The sirens, which were taken offline in 2019 to address security vulnerabilities, will provide an additional method to communicate critical public safety messages in the event of an emergency or disaster
August 24, 2023

San Francisco, CA – Mayor Breed joined Board of Supervisors President Aaron Peskin today to announce plans to prioritize upgrading the City’s Outdoor Public Warning System (OPWS) during the Mayor’s Disaster Council meeting, which is convened to discuss emergency preparedness plans and initiatives. The necessary upgrades will secure the system from hacking and allow the City to bring the sirens back after 4 years of silence.    

During today’s meeting, the Department of Emergency Management (DEM) presented an overview of San Francisco’s current alert and warning systems to Mayor Breed, Board President Peskin, City leaders and community stakeholders. In 2019, the aging OPWS was taken off-line to address serious security vulnerabilities that made the sirens susceptible to being hacked and manipulated, which presented a clear and immediate threat to the public safety of all residents.   

“Anyone who lived in San Francisco before December 2019 knows all too well the familiar Tuesday noon sirens test and the assurance that came with this safety message that boomed throughout the City,” said Mayor London Breed. “The recent devastation in Maui was a tragic example of how important emergency notifications to residents, businesses and tourists are, and although we historically have had minimal need to use the sirens in San Francisco, we must be ready when the time comes. This additional tool will bolster our City’s existing comprehensive alert and warning system.”   

“While I was initially disappointed that this critical investment in our public safety infrastructure was not funded in the City’s Capital Plan, I am delighted that we were able to collaborate and find funds to finally get the Warning System back up and running,” said Board of Supervisors President Aaron Peskin.  

Prior to the pandemic, the City began exploring funding options to upgrade the system to include new hardware and encryption technologies, with priority upgrades dedicated to the 27 sirens along the coast, which would be of most benefit during a tsunami. Since then, the City has been able to expand the use and adoption of other warning systems, such as AlertSF, while focusing financial resources on citywide public health response and public safety staffing, and working to close a $780 million budget deficit.  

In response to a rapidly changing climate in San Francisco and recent devastation in Maui, Mayor Breed has directed DEM and the Department of Technology (DT) to upgrade and fully restore the Outdoor Public Warning System. As part of this plan, DEM and DT will engage experts in this field to assess current technologies and best practices in outdoor public warning system technologies and determine the system overhaul implementation plan and timeline. Once approved, the first phase of the OPWS upgrade and implementation is expected to commence within the next six months. Current cost estimates for initial upgrades are approximately $5 million.  

“San Francisco’s integrated emergency alert and warning systems are robust and overlapping and our City has made considerable investments in conventional platforms, technology-based solutions, and community-based networks,” said DEM Executive Director, Mary Ellen Carroll. “Even so, having as many tools as possible to alert the public is always helpful during a critical situation. Bringing back the outdoor public warning sirens adds an additional layer of redundancy to our overall alert and warning system in San Francisco.”   

“For several years, the City’s ability to fund capital investments has been greatly impacted by the COVID emergency and budget deficits. I am grateful to Mayor Breed and President Peskin for their efforts to secure funding to upgrade the OWPS, which will add an additional layer of communication to alert and warn residents during emergencies,” said City Administrator Carmen Chu. “My office will continue to work with departments, the Mayor, and the Board of Supervisors to evaluate budget priorities and secure our City’s critical infrastructure.”   

Over the last decade, San Francisco and cities everywhere have increasingly faced worsening weather and air quality conditions caused by climate change. In January and March of this year, San Francisco experienced historic storms that flooded streets, downed trees and utility pools, and caused shards of glass to break on some of the City’s tallest buildings. Additionally, the Bay Area region continues to contend with increasing wildfires, and most recently, the state prepared for Hurricane Hilary impacting Southern California as it made landfall as a tropical storm, which is the first in the state in more than 80 years.    

The City’s Outdoor Public Warning System is only one of many alert and warning tools DEM uses to inform the public about emergencies. Other alerting tools include government wireless emergency alerts (WEA) that can send emergency messages to any cell phone within a specific geographic area. The City can also rely on the emergency alerting system (EAS) to broadcast warning messages to the public via cable, satellite, or broadcast television, and both AM/FM and satellite radio. However, the most used system is AlertSF, San Francisco's opt-in emergency alert system that allows DEM to send email and text messages as well as phone calls to voice over internet and landlines about emergency situations and what to do to be safe.   

Anyone who lives in, works in or visits San Francisco is urged to sign of for AlertSF by texting relevant zip code(s) to 888-777 or by signing up online at